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2 – 4 November, 2018
Tongji University, Shanghai, China
Engineering Mechanics Institute
International Conference 2018
Sponsored by
Tongji University
National Natural Science Foundation of China
The Chinese Society of Theoretical and Applied Mechanics
Architectural Society of China
Shanghai Society of Theoretical and Applied Mechanics
Chinese Society for Vibration Engineering
1687
ASCE
EMI ENGINEERINGMECHANICSINSTITUTE
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
1
TableofContents
WELCOME FROM THE EMI PRESIDENT ....................................................................................... 2
Background and Aim ..................................................................................................................... 3
Conference Co-Chairs .................................................................................................................... 3
EMI Administrative Staff ............................................................................................................... 3
2018 EMI Board of Governors ...................................................................................................... 3
Committee ...................................................................................................................................... 4
Poster Session ................................................................................................................................ 6
Conference Venue .......................................................................................................................... 7
Contacts .......................................................................................................................................... 8
Program ........................................................................................................................................... 9
PlenaryLectures ............................................................................................................................ 24
Abstracts ........................................................................................................................................ 32
MS1: Cementitious Materials: Experiments and Modeling across the Scales ................................... 33
MS2: Modeling Time-Dependent Behavior and Deterioration of Concrete ...................................... 49
MS3: Instabilities and Bifurcations in Solids, Structures and Soft Materials ..................................... 57
MS4: Computer Vision-based Studies in Structural Health Monitoring ............................................. 80
MS5: Nonlinear Stochastic Structural Dynamics Methodologies for Complex Engineering Systems 83
MS6: Damage Modelling of Engineering Structures .......................................................................... 86
MS7: Non-Deterministic Modelling and Uncertainty Management in Structural Dynamics and
Vibroacoustics .................................................................................................................................... 93
MS8: Computational Modeling of Damage and Failure in Solids and Structures ............................ 106
MS9: Reliability Analysis of Engineering Structures under Disastrous Excitations .......................... 110
MS10: Damage and Fracture of Brittle and Quasi-Brittle Materials ................................................ 119
MS12: Dynamic Analysis and Seismic Performance of Structures under Strong Earthquake Ground
Motions ............................................................................................................................................ 124
MS13: Damage and Failure Modeling and Analysis of Concrete and Structures ............................. 143
MS14: Uncertainty Quantification and Reliability-based Performance Evaluation ......................... 153
MS15: Environmental Effects on the Properties of Cementitious Materials: Experiments, Modeling
and Simulation ................................................................................................................................. 183
MS16: Fluid-Structure Interactions and Flow-Induced Motions ...................................................... 194
MS17: Stability and Failure of Structures and Materials.................................................................. 200
MS18: Computational Modeling of Advanced Materials and Novel Structural Systems for Hazard
Mitigation ......................................................................................................................................... 214
GS1: Stochastic Mechanics and Structural Reliability ...................................................................... 221
GS2: Computational Mechanics ....................................................................................................... 227
GS3: Wood Mechanics ..................................................................................................................... 238
GS4: Structural Mechanics and Simulation ...................................................................................... 243
GS5: Bio-Mechanics and Bone Mechanics ....................................................................................... 253
The 5th EMI International Conference 2019 .......................................................................... 255
Join EMI Today ........................................................................................................................... 257
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
2
WELCOME FROM THE EMI PRESIDENT
DearParticipantsofthe2018EMIInternationalConference,
AsIstartmysecondyearofserviceasPresidentofEMI,Iwouldliketoexpressmy
sincere thanks to the extraordinary dedication, commitment and hard work of the
BoardofGovernors,theEMIstaff,thetechnicalcommittees,andourmembersinthe
U.S.andaroundtheglobe.OnbehalfofEMI,IwouldliketothankProf.JieLi(Tongji
University),ConferenceChair,Prof.JianbingChen(TongjiUniversity),Prof.Xiaodan
Ren (Tongji University), and Prof. Jian-Ying Wu (South-China University of
Technology),Co-ChairsoftheLocalOrganizingCommittee,fororganizingandhosting
thisyear'sEMIInternationalConference.Iwouldalsoliketothankallthemembers
oftheLocalOrganizingCommitteeandallthemembersoftheInternationalScientific
Committeefortheirvaluablecontributionstothesuccessoftheconference.
The ever-increasing attendance at the EMI conferences reflects EMl's growing
reputationasthepremiervenueforengineeringmechanics.Inadditiontothevibrant
technicalprogramsofferedoverthepasttenyearsatEMIconferences,ourInstitute
hasexperiencedahealthyincreaseinitsmembershipandhasgreatlybenefitedfrom
the stellar reputation of our flagship publication, the ASCE Journal of Engineering
Mechanics, under the inspiring editorship of Prof. Roberto Ballarini (University of
Houston).
Iinviteyoutogetmoreinvolvedwithourinstitute.EMIwillfurthergrowandthrive
only if the requisite hard work is shared among its members. Opportunities for
engagement includepublication intheASCEJournalofEngineeringMechanicsand
theLectureNotesinMechanicsSeries,activeparticipationontechnicalcommittees,
organizationofconferencesessionsandsymposia,engagementintheEMIindustry
collaboration,deliveryofwebinars,andseekingleadershiprolesoncommitteesand
theBoardofGovernors.
Iwishyouanenjoyableandproductiveconference.
Yourstruly,
ProfessorGeorgeDeodatis
ColumbiaUniversity,NewYorkCity
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
3
Background and Aim
CreatedonOctober1,2007,theEngineeringMechanicsInstitute(EMI)replacestheformer
ASCE Engineering Mechanics Division. EMI has two annual conferences, one in the United
Statesandanotherinternationally.Theseconferencesofferaplacetoexchangeideas,present
your work, and see what others are doing. The fundamental advances in engineering
mechanicsarehereondisplay.Theseconferencespresentpremieropportunitiestonetwork
with leaders in the field,expandyourhorizons,andestablishprofessionalrelationships to
advanceyourresearchandyourcareer.EMIconferencesalsoshowcasesomeofthebrightest
studentswhoparticipateinstudentcompetitions.
The 2018 EMI International Conference will be held at Tongji University, Shanghai, China
during Nov. 2-4th, 2018. This event will be a forum to present the newest findings and to
depict the future development in Engineering Mechanics as the core discipline of science-
enabledCivilEngineeringunderstoodinthebroadestsense.
Conference Co-Chairs
JieLi,TongjiUniversity
GeorgeDeodatis,ColumbiaUniversity
EMI Administrative Staff
AmarChaker,ASCE/EMI
VernaJameson,ASCE/EMI
2018 EMI Board of Governors
GeorgiosDeodatis,Ph.D.,F.EMI,M.ASCE,President
PolD.Spanos,Ph.D.,P.E.,NAE,F.EMI,Dist.M.ASCE,VicePresident
Jiun-ShyanChen,Ph.D.,F.EMI,M.ASCE,PastPresident
AmarA.Chaker,Ph.D.,F.AEI,F.EMI,F.ASCE,Secretary
SomnathGhosh,Ph.D.,Ph.D.,F.EMI,M.ASCE,Treasurer
GianlucaCusatis,Ph.D.,F.EMI,M.ASCE.Member
RaymondDaddazio,Sc.D.,P.E.,F.EMI,M.ASCE,Member
GlaucioH.Paulino,Ph.D.,F.EMI,M.ASCE,Member
AntoinetteTordesillas,Ph.D.,Aff.M.ASCE,Member
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
4
Committee
InternationalScientificCommittee
AhmerWadee ImperialCollegeLondon UK
Bao-FengHuang NanjingTechUniversity China
BernhardPichler TUWien-ViennaUniversityofTechnology Austria
CaoSun LouisianaStateUniversity USA
Chao-LieNing TongjiUniversity China
ChristianHellmich TUWien-ViennaUniversityofTechnology Austria
Da-XuZhang ShanghaiJiaoTongUniversity China
De-ChengFeng SoutheastUniversity China
DingWang YanshanUniversity China
Di-XiongYang DalianUniversityofTechnology China
FanKong WuhanUniversityofTechnology China
FanXu FudanUniversity China
Franz-JosefUlm MassachusettsInstituteofTechnology USA
GianlucaCusatis NorthwesternUniversity USA
GillesPijaudier-Cabot UniversitédePauetetdesPaysdel’Adour France
GiovanniDiLuzio PolitecnicodiMilano Italy
GüntherMeschke RuhrUniversityBochum Germany
Hai-YanHu BeijingInstituteofTechnology China
HerbertMang ViennaUniversityofTechnology;TongjiUniversity Austria
Hong-ZheDai HarbinInstituteofTechnology China
IoannisKougioumtzoglou ColumbiaUniversity USA
IoannisMitseas LeibnizUniversityHannover Germany
JanVorel CzechTechnicalUniversityinPrague Czech
JianYang ShanghaiJiaoTongUniversity China
JianZhang UniversityofCaliforniaatLosAngeles USA
Jian-BingChen TongjiUniversity China
Jian-GuoCai SoutheastUniversity China
Jian-YingWu SouthChinaUniversityofTechnology China
JieLi TongjiUniversity China
Ji-FengXu BeijingAeronauticalScience&TechnologyResearchInstitute China
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
5
Jing-QuanWang SoutheastUniversity China
Jin-GuangTeng HongKongPolytechnicUniversity China
Jiun-ShyanChen UniversityofCalifornian.SanDiego USA
JunXu HunanUniversity China
Li-HuaJin UCLA.California USA
LinWan-Wendner PolitecnicodiMilano Italy
LiuJin BeijingUniversityofTechnology China
LoriGraham-Brady JohnsHopkinsUniversity USA
MatteoBroggi LeibnizUniversitätHannover Germany
MengChu TongjiUniversity China
MichaelBeer LeibnizUniversitätHannover Germany
MichelPotier-Ferry UniversityofLorraine France
MohamedMoustafa UniversityofNevada. USA
MohammadJahanshahi PurdueUniversity USA
NingZhang McNeeseStateUniversity USA
RomanWan-Wendner UniversityofNaturalResourcesandLifeSciences Austria
Si-FengBi LeibnizUniversitätHannover Germany
Tian-CanHuang GuangzhouUniversity China
Xiao-DanRen TongjiUniversity China
Xiao-YingZhuang TongjiUniversity China
YangXiang WesternSydneyUniversity Australia
Yan-PingCao TsinghuaUniversity China
Yi-BinFu KeeleUniversity UK
Yong-ZhongHuo FudanUniversity China
You-BaoJiang ChangshaUniversityofScienceandTechnology China
ZdeněkBažant NorthwesternUniversity USA
Zhao-DongDing HeFeiUniversityofTechnology China
Zhen-HaoZhang ChangshaUniversityofScienceandTechnology China
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
6
LocalOrganizingCommittee
Co-Chairs
Jian-BingChen TongjiUniversity
Xiao-DanRen TongjiUniversity
Jian-YingWu South-ChinaUniversityofTechnology
Members
Xiang-LingGao TongjiUniversity Yan-PengWang TongjiUniversity
WeiLiu TongjiUniversity QingWang TongjiUniversity
Yong-BoPeng TongjiUniversity Ling-YingKong TongjiUniversity
HaoZhou South-ChinaUniversityofTechnology Zhi-QiangWan TongjiUniversity
Shi-XueLiang ZhejiangSCI-TECHUniversity Yu-PengSong TongjiUniversity
YeFeng TongjiUniversity Meng-ZeLyu TongjiUniversity
LuHai TongjiUniversity
Poster Session
PosterSessionwillbeheldattheB-flooroftheSino-FrenchCenterofTongjiUniversityduringthe
conference.PresentersshouldputupyourpostersonthemorningofNovember3th.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
7
Conference Venue
Conferencevenue:TongjiUniversity
Address:1239SipingRoad,Shanghai,China
MapofVenue
Sino-FrenchCenter
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
8
Transportation
(1)FromPudongInternationalAirport(PVG)
☞byMetroLine2to“EastNanjingRoad”andtransferMetroLine10to“TongjiUniversity”stop(about100
minutes/RMB7.00)
☞byTaxi(about60minutes/RMB160.00)
(2)FromHongqiaoInternationalAirport(SHA)orHongqiaoRailwayStation
☞byMetroLine10tothe“TongjiUniversity”stop(about60minutes/RMB5.00)
☞byTaxi(about50minutes/RMB110.00)
(3)FromShanghaiRailwayStation
☞byMetroLine4to“HailunRoad”andtransferMetroLine10to“TongjiUniversity”stop(about40minutes
/RMB4.00)
☞byTaxi(about30minutes/RMB40.00)
(4)FromShanghaiSouthRailwayStation
☞byMetroLine3to“HongqiaoRoad”andtransferMetroLine10to“TongjiUniversity”stop(about70
minutes/RMB5.00)
☞byTaxi(50minutes/RMB90.00)
Contacts
Jian-BingChen,Professor
CollegeofCivilEngineering,TongjiUniversity,Tel:+86-13761804958,E-mail:[email protected]
Xiao-DanRen,AssociateProfessor
CollegeofCivilEngineering,TongjiUniversity,Tel:+86-15821525391,E-mail:[email protected]
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
9
Program
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
10
Time Venue
14:00—21:30Registration
The3rdfloorofKingswellHotelVIPRoom
19:00—21:00IceBreakerReception
The3rdfloorofKingswellHotelBallRoom
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Time Venue
8:00—18:00 Registration(Sino-FrenchCenterRoomC201)
8:30—8:50 WelcomingRemarks
8:50—9:00 GroupPhoto
PlenaryLectures
Chair(s):Prof.PolD.Spanos
9:00--9:40DesignofNewMaterialsandStructurestoMaximizeStrengthatProbabilityTail:ANeglectedChallengeforQuasibrittleandBiomimeticMaterials
Prof.ZdeněkP.Bažant-NorthwesternUniversity,USA
9:40--10:20EngineeringDynamicsofSoftMachines
Prof.Hai-YanHu-BeijingInstituteofTechnology,P.R.China
10:20--10:40 CoffeeBreak(The1stfloorofSino-FrenchCenter)
Sino-FrenchCenter
RoomC201Sino-FrenchCenter
RoomC401YifuBuilding
Room113Sino-FrenchCenter
RoomA401TongjiUniversityZhonghe
BuildingRoom1002TongjiUniversityZhonghe
BuildingRoom802
Session
MS3:Instabilitiesand
BifurcationsinSolids,StructuresandSoft
MaterialsChair(s):Yong-ZhongHuo
MS10:DamageandFractureofBrittleandQuasi-Brittle
MaterialsChair(s): Da-XuZhang
MS2:ModelingTime-DependentBehaviorandDeterioration
ofConcreteChair(s):LinWan-Wendner
MS14:UncertaintyQuantification
andReliability-basedPerformanceEvaluation
Chair(s):Zhen-HaoZhang
MS17:StabilityandFailureof
StructuresandMaterialsChair(s):XiangYang
Ji-FengXu
MS9:ReliabilityAnalysisof
EngineeringStructuresunderDisastrousExcitations
Chair(s):JunXu
10:40—10:55
A0121(Invited):WrinklingofSoft
Biomaterials
A0978:ImpactFractureSimulation
ofMonolithicandLaminatedGlassUsing
HybridDiscontinuaandContinuaMethod
A0042:ConcreteCreepModeling:
ApplicationtoSlabsonGround
A0131(Invited):AnalyzingComplex
SystemsunderEpistemicUncertainties
A0839(Invited):FailureandBuckling
AnalysesofCompositeLaminateswithCut-Outs:TheoryandExperiments
A0022(Invited):AProbabilisticAnalysisofa
PhenomenologicalModelforStructuralCollapse
Simulation
Xing-ErWang YaWei
10:55--11:10
A0857:ModellingofDamageandFractureofPlainWeave
CeramicMatrixCompositesunderUni-AixalTension
A0082:NumericalModule
DevelopmentfortheEntireProcessofRCDeterioration
duetoNon-UniformCorrosion
BoLi Da-XuZhang Zhao-ZhengMeng MichaelBeer Jian-XiangWang ChengChen
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11:10--11:25
A0342:Photo-ResponsiveSurface
WrinklingPatterns
A0863:PredictionofShear
DamageBehaviourofFibre-ReinforcedCeramic
MatrixTows
A0287:AgeDependentShear
ResistanceofReinforcedandPrestressedConcrete
A0644:ProbabilityDistrubutionoftheTimeIntervalBetween
TwoAdyacentRandomEventsoftheWiener
ProcessCrossingaBoundary
A0149:FrequencyAnalysisfor
VibratingBendingBeamsviaaNewStaticApproach
A0824:AssessingtheSpallingofTunnelLiningsSubjected
toFireLoading
Cong-HuaLu Da-XuZhang LinWan-Wendner Zhen-HaoZhang Zhen-YuChen Yi-MingZhang
11:25--11:40
A0250:MechanicsofNanofibers
PackinginVesicles:EffectsofFiberLength,Radius,
andElasticity
A0866:ValidationoftheCombinedFEM-DEMonModeIandIIConcreteRuptureSubjectstoSemi-CircularBending
A0708:ATheoreticalFramework
forCreepEffectAnalysisofAxialLoadedShortCFST
ColumnsunderHighStressLevels
A0222:MultiLevelMoving
ParticlesSimulationforReliabilityAssessmentwith
ApproximateLimiteStateFunctions
A0586:BucklingofBeamsSubject
toInfluenceofSurfaceStresses
A0349:StochasticDynamic
ResponseAnalysisandReliabilityAssessmentof
Non-LinearStructuresunderFullyNon-Stationary
GroundMotions
XinYi Xu-DongChen Shi-WeiLi CarstenProppe FengLin JunXu
11:40--11:55
A0397:AConsistentFinite-StrainPlateTheoryforGrowth-
InducedDeformationsandInstabilitiesofSoftMaterial
Samples
A0034:InfluenceofAsphalt
MixtureTypeonStrengthSizeEffectStatisticsatLow
Temperature
A0593:ProbabilisticModeloftheYieldingStrengthforthe
CorrodedRebars
A0949:StructuralFailureMode
IdentificationandReliabilityAnalysisbased
onMulti-ResponseSurfaceMethod
A0380:PLY-GAPEffectson
BucklingBehaviorofCompositeConicBarrelby
AutomatedFiberPlacement
A0347:SimulationofStationary
Non-GaussianVectorProcesswithinWave-
PassageEffectbasedonSpectralRepresentation
Method
JiongWang AugustoCannoneFalchetto Xiang-LingGao ZhaoChen Tian-LiangQin Yong-XinWu
11:55--12:10
A0054:PatternTransitionsina
SoftCylindricalShell
A0098:ConcreteShearWalls
AffectedbyAlkali-SilicaReactionPartI:Testing
A0549:StudyonMechanical
PropertiesandDamageAssessmentforCollided
Concrete
A0590:ThermalPostbuckling
BehavioursofFunctionallyGradedNanocomposite
Plates
A0538:ImpactofInitialDamage
PathandSpectralShapeonAftershockCollapse
FragilityofRCFrames
FanXu ShamimSheikh X.Y.Liu YinFan Xiao-HuiYu
12:20--13:30 Lunch(The1stfloorofKingswellHotelSunshineCoffeeShopandthe3rdfloorofKingswellHotelNo.3Room)
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Sino-FrenchCenterRoomC201
14:00--14:40
PlenaryLectureChair(s):Prof.RobertoBallarini
MechanicsofinterfacesinFRP-strengthenedstructures
Prof.Jin-GuangTeng-SouthernUniversityofScienceandTechnology,P.R.China
Sino-FrenchCenter
RoomC201Sino-FrenchCenter
RoomC401YifuBuilding
Room113Sino-FrenchCenter
RoomA401TongjiUniversityZhonghe
BuildingRoom1002TongjiUniversityZhonghe
BuildingRoom802
Session
MS3:Instabilitiesand
BifurcationsinSolids,StructuresandSoft
MaterialsChair(s):Xi-QiaoFeng
MS1:CementitiousMaterials:
ExperimentsandModelingAcrosstheScales
Chair(s):BernhardPichler
MS12:DynamicAnalysisand
SeismicPerformanceofStructuresunderStrong
EarthquakeGroundMotions
Chair(s):ErtugrulTacirogluYi-QiangXiang
MS14:UncertaintyQuantification
andReliability-basedPerformanceEvaluationChair(s):MichaelBeer
MS17:StabilityandFailureof
StructuresandMaterialsChair(s):ZhengLi
Ji-FengXu
MS9:ReliabilityAnalysisof
EngineeringStructuresunderDisastrousExcitations
Chair(s):DingWang
14:50--15:05
A0154(Invited):MorphologicalEvolutionofBuckle-Delamination:fromTelephoneCordBlisterto
Beyond
A0919:Microstructural
CharacterizationoftheSpunCastConcrete
A0105:DimensionalSeismicResponsesofShear-
FlexuralBeamandSelf-SimilarInterstoryDrift
Spectrum
A0915:RiskPriorityNumbersforVariousFailuresinBridges
A0681: Imperfectionsbydesign:interactivebucklingand
postbucklinginarchitectedmaterials
A0563:StructuralReliability
AnalysisUsingUQFEMSoftware
MaciejSobótka Gui-QiangGuo ChandrasekharPutcha NanHu Zi-QiWang
15:05--15:20
A0761:Time-SpaceDependent
StabilityAnalysisofShallowNatmTunnelswith
DiscontinuityLayoutOptimization
A0109:ANewApproachtoDesignExplicitTimeIntegration
AlgorithmwithNumerical
A0179:EfficientBridgeLifetime
AssessmentbyTrafficLoadModelUpdatingandSubset
Simulation
A0332:Characterizationof
nonlinearconstitutivebehaviorofceramic-based
compositeusingdigitalimagecorrelation
A0520:SeismicFragilityAnalysis
ofUrbanRoadNetwork-ACaseStudyonTangshan
City
YongNi Yi-MingZhang ShiLi He-QingMu Xiao-HuiJI DingWang
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15:20--15:35
A0493:PatternFormationin
CurvedFilm-SubstrateSystems
A0038:Macro-ScaleStrengthand
MicrostructureofZrW2O8CementitiousComposites
withTunableLowThermalExpansion
A0567:ModelingandPerformance
AssessmentofBase-IsolatedBuildings
A0912:AnalyticalSolutionfor
LocalBucklingStrengthofSquareCFTColumns
SubjectedtoEccentricCompression
A0473:CharacterizationforCompression-Shear
CombinedPropertiesofaCompositeMaterial
A0577:SeismicReliabilityAnalysis
ofEnergy-DissipationBridgeStructuresUsing
HamiltonianMonteCarloBasedSubsetSimulationinConjunctionwithExplicit
TimeDomainDimensionalityReduction
MichelPotier-Ferry Yang-BoLi NicholasOliveto Yu-lingLong Ti-RenHe Shao-MinJia
15:35--15:50
A0061:AModelingandResolutionFrameworkforWrinklinginHyperelasticSheetsat
FiniteStrain
A0283:Multiscale
ThermomechanicalAnalysisofReinforced
ConcreteBeamsSubjectedtoSuddenHeating
A0355:CollapsePerformance
AssessmentofSelf-CenteringPrecastConcreteWallswithDifferentPost-
TensioningandEnergyDissipationDesigns
A0753:APolynomialElement
BasedGalerkinApproachfortheSimulationof
MultivariateRandomFields
A0384:SeismicPerformanceofUnreinforcedMasonry
WallswithBoundaryRCFrame
Chen-BoFu HuiWang HaoWu Xu-FangZhang Young-ChanYou
15:50--16:10 CoffeeBreak(The1stfloorofSino-FrenchCenter)
Session
MS3:Instabilitiesand
BifurcationsinSolids,StructuresandSoft
MaterialsChair(s): FanXu
MS1:CementitiousMaterials:
ExperimentsandModelingAcrosstheScales
Chair(s): Yi-MingZhang
MS7:Non-deterministic
modellinganduncertaintymanagementinstructural
dynamicsandvibroacoustics
Chair(s):MichaelBeer
MS14:UncertaintyQuantification
andReliability-basedPerformanceEvaluationChair(s): Hong-ZheDai
MS6:Damagemodellingof
engineeringstructuresChair(s): LuHai
MS15:EnvironmentalEffectson
thePropertiesofCementitiousMaterials:
Experiments,ModelingandSimulation
Chair(s):TaoLi
16:10--16:25
A0089(Invited):Morphable3D
MesostructuresandMicroelectronicDevicesby
MultistableBucklingMechanics
A0139:StrengtheningEffectofCementitiousMaterials
SubjectedtoHigh-DynamicLoading
A0439(Invited):TheBhattacharyyaDistance:ANovel
UncertaintyQuantificationMetricinStochasticSensitivityAnalysis
A0944:ReliabilityAnalysisof
SeismicCapacityofShearWallConsideringPossible
TensionFailureandRandomEccentricity
A0169(Invited):ConcurrentFatigueCrack
GrowthandVehicle-BridgeDynamicsAnalysisUsing
Time-basedSybcycleFormulation
A0953(Invited):Multi-PhaseModellingof
Multi-speciesTransportinCementitiousMaterials:In
caseofElectrochemicalRehabilitation
EvaBinder Yan-BiaoWang
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16:25--16:40
A0089(Invited):Morphable3D
MesostructuresandMicroelectronicDevicesby
MultistableBucklingMechanics
A0198:MultiscaleModelingof
CementitiousMaterials:FromHydrationviaMicrostructureto
MacroscopicProperties
A0439(Invited):TheBhattacharyyaDistance:ANovel
UncertaintyQuantificationMetricinStochasticSensitivityAnalysis
A0558:ANovelMachineLearning-
BasedMethodtoPredictMemberBucklingfor
SquarePyramidSpaceGridStructure
A0169(Invited):ConcurrentFatigueCrack
GrowthandVehicle-BridgeDynamicsAnalysisUsing
Time-basedSybcycleFormulation
A0953(Invited):Multi-PhaseModellingof
Multi-speciesTransportinCementitiousMaterials:In
caseofElectrochemicalRehabilitation
Yi-HuiZhang BernhardPichler Si-FengBi QianZhang Yong-MingLiu Qing-FengLiu
16:40--16:55
A0433:ControllableRollingandConfigurableBendingin
FlexibleNanomemrbanes
A0244:Investigationofthe
Shrinkage-VolumetoSurfaceRatioRelationship
inCementConsideringCracking
A0044:StructuralReliabilityand
ReliabilitySensitivityAnalysisofExtremelyRare
FailureEventsbyCombiningSamplingandSurrogateModelMethods
A0540:EstimatingUncertaintyinLimitStateCapacitiesfor
ReinforcedConcreteFrameStructuresThroughPushoverAnalysis
A0879:ConstitutiveModelingof
DuctileandBrittleFailuresofSemicrystalline
Polymers
A0526:ExperimentalResearchonDynamicCharacteristicsofCrumbRubberConcreteat
LowTemperature
Yong-FengMei Yi-GeZhang Peng-FeiWei Xiao-HuiYu Jia-LiangLe GangXue
16:55--17:10
A0715:Electromechanical
Catastrophe
A0691:InsightintotheRoleofInterfacialBoltsontheStructuralBehaviorof
SegmentalTunnelRings
A0323:ModelingtheAsymmetricDependentSoilVariables
A0203:StochasticStayCableForceModelingUsingMonitoring
DatafromaCable-stayedBridge
A0477:MachineLearningbasedMultiscaleModelingof
BackwardErosionPiping
A0805:StochasticDynamical
BehaviorsofCorrosionReactionSystemin
ConcreteSubjectedtoExternalSulfateAttack
Tong-QingLu Jiao-LongZhang YiZhang MichaelHai-JunZhou AlessandroFascetti TaoLi
17:10--17:25
A0026:ActuatingSoftMaterialsinSurgeryRobotApplications
A0736:Meso-FiniteElement
FractureAnasysisforFiberReinforcedEmulsified
Asphalt-CementConcrete
A0079:Model-FormandParameterUncertaintyQuantification
inStructuralVibrationSimulationUsingFractional
Derivatives
A0389:PrestressedConcrete
BeamsFailingduetoWeb-Crushing:Uncertaintyand
ReliabilityAnalysis
A0827:ScalingEffectsforDynamic
ResponseswithApplicationtoBuriedArchesSubjectedto
InternalBlast
A0812:StochasticModelingof
SulfateIonDiffusionCoefficientattheConcrete-
SolutionInterface
BoLi JunFu Bao-QiangZhang OladimejiBenedictOlalusi SzeDaiPang Shan-ShanWang
Pro
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17:25--17:40
A0426:EdgeWrinklingofaSoft
RidgewithGradientThickness
A0028:Performanceofthe
ConcreteFreefromSteelReinforcement
A0535:ABayesianMethodfor
JointParameterOptimalEstimationbasedonPower
SpectralDensity
A0830:QuantifyingPost-disasterFunctionalityLossesandRecoveryofCommunity
BuildingPortfolios
A0451:SimulatingTime-
DependentQuasi-BrittleFailuresbasedona
MultilinearReleasingMechanismofViscous
ForceFields
A0966:ResearchonMoisture
TransportofCement-basedMaterialsBasedonLowFieldNuclearMagnetic
Resonance
YanZhao Jiang-TaoYu ZhangYong Nai-YuWang Jin-XingLiu XiaWu
17:40--17:55
A0483:LocalizedBulginginan
InflatedBilayerTube
A0651:AnalysisofSeismic
CollapseofHigh-RiseStructureunderNear-FaultPulse-TypeGroundMotion
YangLiu Tian-CanHuang
18:30--21:00 Banquet(The15thfloorofShanghaiJinjiangMetropoloHotel)
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Engineering Mechanics Institute
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Time Venue
Sino-FrenchCenterRoomC201
8:30--9:50PlenaryLectures
Chair(s):Prof. GeorgeDeodatis
8:30--9:10
AnalysisofConcreteStructures
AJointResearchProjectofTongjiUniversityandViennaUniversityofTechnology
Prof.HerbertMang-ViennaUniversityofTechnology,Austria;TongjiUniversity,P.R.China
9:10--9:50UncertaintyPropagationfromMaterialsCharacterizationtoModeling
Prof.LoriGraham-Brady-JohnsHopkinsUniversity,USA
9:50--10:10 CoffeeBreak(The1stfloorofSino-FrenchCenter)
Sino-FrenchCenter
RoomC201Sino-FrenchCenter
RoomC401YifuBuilding
Room113Sino-FrenchCenter
RoomA401TongjiUniversityZhonghe
BulidingRoom1002TongjiUniversityZhonghe
BulidingRoom802
Session
MS18:ComputationalModelingof
AdvancedMaterialsandNovelStructuralSystems
forHazardMitigationChair(s): Mohamed
Moustafa
MS12:DynamicAnalysisand
SeismicPerformanceofStructuresunderStrong
EarthquakeGroundMotions
Chair(s): ZhengHeDi-XiongYang
MS7:Non-Deterministic
ModellingandUncertaintyManagementinStructural
DynamicsandVibroacoustics
Chair(s): Jian-BingChen
MS14:UncertaintyQuantification
andReliability-basedPerformanceEvaluation
Chair(s): Da-GangLu
MS13:DamageandFailure
ModelingandAnalysisofConcreteandStructures
Chair(s): Zhao-DongDing
GS4:StructuralMechanicsand
SimulationChair(s): HaoZhou
10:10--10:25
A0368:SectionandFiniteElementAnalysisofSeismicUHPCPierswithHighStrength
Steel
A0112(Invited):RecentAdvancesin
EngineeringCharacteristicsofNear-FaultGroundMotionsandSeismic
EffectsofBuildingStructures
A0145(Invited):ARobustApproachto
QuantifyingForecastingUncertaintyUsingProxy
Simulations
A0518(Invited):GlobalDynamicSeismic
ReliabilityAnalysisforRCFrameStructuresUsingNT-
ANN
A0970(Invited):AnEquivalentStrainbasedMulti-ScaleDamageModel
ofConcrete
A0259:AParallelSpectralElementMethodfortheSimulation
ofScalarElasticWaves
MohamedMoustafa SeungwookYoun
10:25--10:40
A0363:Multi-PhysicsSimulationonPassivePatchAntennaSensorforWirelessStrain
Measurement
A0267:ANumercalStudyonthe
Thermo-MechanicalResponseofaComposite
BeamExposedtoFire
DanLi Di-XiongYang ScottCogan Da-GangLu Shi-XueLiang MoonSooKang
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10:40--10:55
A0729:PrimaryStructural
ConfigurationInvestigationofaNovelCouplingArmConnectingTwoFloating
Structures
A0313:FeaturesofOffshore
SeismicGroundMotionsDistinctfromtheOnshore
A0129:DynamicResponseofaTrain-BridgeIntractionSystemduetoSudden
DecelerationinHighSpeedRailwaySystems
A0020:RobustStatisticalMethods
forPowerSpectrumEstimationfromMultiple
SourceRecords
A0124:MultilevelModelingof
Fiber-ReinforcedConcreteandSimulationofCrackinginTunnelLiningSegments
A0310:TheoreticalStudyonVibrationofaSimply
SupportedFootbridgeunderDiscretePedestrian
Loading
TaoLi QiZhang Xu-ZhaoLu MarcoBehrendt Yi-JianZhan Shih-HsunYin
10:55--11:10
A0321:EnhancingSeismic
PerformanceofPorcelainElectricalEquipmentUsing
BaseIsolation
A0523:DynamicTestingofaFull-
ScaleFrp-RetrofittedReinforcedConcrete
BuildingFrame
A0414:Non-ProbabilisticModelofTransmissibilityFunctionsbasedonComplexInterval
Arithmetic
A0440:Identificationof
PerformanceDegradationModelbasedonStandard
WienerProcess
A0274:NumericalInvestigationof
ConcreteAgeEffectonShearLoadCapacityofPost-InstalledAnchors
A0721:Non-LinearNumerical
AnalysisonOverallProcessMechanicalBehaviorof
Quasi-RectangularSegmentalTunnelLining
WenBai JiukShin Meng-YunZhao XiaoWang RomanWan-Wendner ZhenLiu
Session
MS18:ComputationalModelingof
AdvancedMaterialsandNovelStructuralSystems
forHazardMitigationChair(s):Mohamed
Moustafa
MS12:DynamicAnalysisand
SeismicPerformanceofStructuresunderStrong
EarthquakeGroundMotions
Chair(s):ZhengHeDi-XiongYang
MS5:NonlinearStochasticStructuralDynamics
MethodologiesforComplexEngineeringSystems
Chair(s):Jian-BingChen
MS14:UncertaintyQuantification
andReliability-basedPerformanceEvaluation
Chair(s):Da-GangLu
MS13:DamageandFailure
ModelingandAnalysisofConcreteandStructures
Chair(s):Zhao-DongDing
GS4:StructuralMechanicsand
SimulationChair(s):HaoZhou
11:10--11:25
A0360:CharacterizationandModelingofAdaptive
RubberBearing
A0673:SeismicVulnerabilityof
RailwayNetworkbasedontheRunning-TrainsSafety
Evaluation
A0659:AnEfficientStochastic
ComplexModalAnalysisTechniquefor
NonclassicallyDampedandNonlinearMDOFStructural
Systems
A0423:StructuralFailurePattern
RecognitionandReliabilityAnalysisbasedonMulti-
ResponseSurfaceMethod
A0378:AnalyticalModelof
RockingElementswithDamagedCorners
A0467:ImpactLocationandLoadIdentificationUsingDeep
NeuralNetworks
Y.E.Ji ChengYang IoannisP.Mitseas ZhaoChen Hao-RanCui Jia-MingZhou
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11:25--11:40
A0671:SystemLevelAnalytical,
ExperimentalandHybridSimulationofResilient
HighwayBridges
A0899:Multi-ScaleComprehensive
SimulationofConcreteShearWallModels:
NumericalSimulation
A0802:AHybridSEM‒SMMethod
forSubwayRandomDynamicLoadsInducedbytheFrequency-DependentDynamicPropertiesofRail
Pads
A0580:ANewFractionalMoment
EquationsMethodforNonlinearVibration
Analysis
A0504:Developmentand
IdentificationofHysteresisModelforReinforced
ConcreteColumnsFailinginDifferentModes
A0983:AB-ScanSubsurface
ImagingofGroundCavitiesUsinganElasticWaveFull-
WaveformInversionMethod
SelimGunay Jing-RanHe KaiWei Rui-JingZhang Xin-LiangLyu BoyoungKim
11:40--11:55
A0008:PotentialRisksonUsingDisconnectedCompositeFoundationSystemsinActiveSeismicZones
A0890:StochasticResponse
AnalysisofanOffshoreWindTurbineunderthe
ExcitationsRepresentedbyStochasticHarmonic
Function
A0583:AKriging-Hdmr
MetamodelMethodforSystemReliabilityAnalysis
ofStructures
A0119:AFractureProblemwitha
SurfaceEnergyintheSteigmann-OgdenForm
MohamedElmasry Yu-PengSong Kai-XiangZhang AnnaZemlyanova
11:55--12:10
A0293:OptimalDesignofSMACableRestrainersfor
SeismicProtectionofaLRBIsolatedSimplySupported
HighwayBridge
ShuaiLi
12:20--13:30 Lunch(The3rdfloorofKingswellHotelBallRoom)
Sino-FrenchCenterRoomC201
PlenaryLectureChair(s):Jian-YingWu
14:00--14:40MeshfreeMethods:ProgressMadeAfter20YearsandFutureDirections
Prof.Jiun-ShyanChen–UniversityofCalifornian,SanDiego,USA
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Sino-FrenchCenter
RoomC201Sino-FrenchCenter
RoomC401YifuBuilding
Room113Sino-FrenchCenter
RoomA401TongjiUniversityZhonghe
BulidingRoom1002TongjiUniversityZhonghe
BulidingRoom802
Session
GS3:WoodMechanics
Chair(s): Jan-WillemG.vandeKuilen
MS16:Fluid-Structure
InteractionsandFlow-InducedMotions
Chair(s):NingZhang
GS1:StochasticMechanicsand
StructuralReliabilityChair(s): Wang-JiYan
MS8:ComputationalModelingof
DamageandFailureinSolidsandStructures
Chair(s): Jian-YingWu
MS13:DamageandFailure
ModelingandAnalysisofConcreteandStructuresChair(s): Chao-LieNing
GS4:StructuralMechanicsand
SimulationChair(s): Tian-CanHuang
14:50--15:05
A0968:VariablityinWood/PlantAnatomyAlongtheScales
A0159:Wind-InducedCladdingandStructuralLoadsonLow-RiseBuildingswith
4:12-SlopedHipRoofs
A0227:TowardsStochastic
ModelingofTsunamis
A0392(Invited):MitigatingMesh
DependenceofStochasticComputationof
QuasibrittleFracture
A0604:Three-DimensionalFinite
ElementModellingofUhpfrcJacket-Retrofitted
PiersunderCyclicLoading
A0512:UltimateCapacityofBulge
FormedT-JointsunderBraceAxialCompression
ExcludingtheChordLengthEffect
WolfgangGard ShuaiShao Zhi-HengWang TengTong Fei-LongNie
15:05--15:20
A0308:Developmentofan
AndvancedFE-NumericalMethodforStrengthPredictionofTimberBoardsbasedonthe
Surface
A0442:ApplicationsofImmersed
BoundaryMethodsinHydraulicModeling
A0554:AGenericFrameworkfor
ProbabilisticDamageCharacterisationUsing
UltrasonicGuidedWaveintheFrequencyDomain
A0635:SpatialCorrelationin
DisorderedHeterogeneousMaterials
A0595:Experimentaland
NumericalStudiesofResonanceVibrationofCablesinaFootbridge
ModelunderBiharmonicExcitation
AniKhaloianSarnaghi NingZhang Wang-JiYan Jia-LiangLe Zhao-DongDing WojciechPakos
Session
GS3:WoodMechanics
Chair(s):Jan-WillemG.vandeKuilen
MS16:Fluid-Structure
InteractionsandFlow-InducedMotions
Chair(s):NingZhang
GS1:StochasticMechanicsand
StructuralReliabilityChair(s):Wang-JiYan
MS8:ComputationalModelingof
DamageandFailureinSolidsandStructuresChair(s):Jian-YingWu
GS5:Bio-MechanicsandBone
MechanicsChair(s):Chao-LieNing
GS4:StructuralMechanicsand
SimulationChair(s):Tian-CanHuang
15:20--15:35
A0955:DeformationKineticsfor
WoodMechanics
A0785:ModeInteractionsofDeep-
SeaRiserinShearFlow
A0454:Multidimensional
StochasticDamageModelforConcreteunderFatigue
Loading
A0757:CrackingElementsMethod
forSimulatingMultipleCracks
A0667:TheRelationBetweenCornealHydrationandStiffnessImprovementBecuaseoftheCornealCrosslinkingTreatment
A0903:Understanding
UncertaintiesfromCyclicTestsofShapeMemoryAlloyBarsforSeismic
Application
VandeKuilenJan-Willem Yuan-CenWang Yan-PengWang Yi-MingZhang HamedHatami-Marbini Jin-PengLi
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15:35--15:50
A0957:AnInvestigationofTheDolEffectofWood´inTension
PerpendicularooGrain
A0747:NonlinearParametric
VibrationAnalysisofRadialGates
A0751:AFractionalMomentMethodforReliabilityAnalysisofStructures
undertheSpatiallyVariability
A0633:PhaseFieldModelingof
HydraulicFracturingintheFrameworkoftheTheory
ofPorousMedia
A0870:A3-DimensionalModelling
ComparisonoftheBiomechanicalStabilityofLateralLumbarInterbodyFusionwithUnilateralorBilateralFixationMethod
A0164:HybridIntelligencefor
SolvingComplexEngineeringProblems:An
IntegratedHumanandMachineLearning
Approach
En-ChunZhu Si-YuanWu Xu-FangZhang Chen-YiLuo TengZhang Yong-MingLiu
15:50--16:05
A0960:AnInvestigationofFatigue
FractureofWoodduetoCyclicMoisture_Induced
Stress
A0972:Actively-Controlled
TurbulenceSimulationsandTheirEffectsontheAeroelasticPropertiesof
TypicalBridgeDeckSections
A0811:StochasticAnalysisofPolymerComposites
RupturesatLargeDeformationsModeledbya
PhaseFieldMethod
Qiong-YaoWu Yu-ChaoLv JieWu
16:05--16:25 CoffeeBreak(The1stfloorofSino-FrenchCenter)
Sino-FrenchCenter
RoomC201Sino-FrenchCenter
RoomC401YifuBuilding
Room113Sino-FrenchCenter
RoomA401TongjiUniversityZhonghe
BulidingRoom1002
Session
MS3:InstabilitiesandBifurcationsin
Solids,StructuresandSoftMaterials
Chair(s): MichelPotier-Ferry
MS12:DynamicAnalysisandSeismic
PerformanceofStructuresunderStrongEarthquakeGround
MotionsChair(s): Jing-QuanWang
JiukShin
MS17:StabilityandFailureofStructures
andMaterialsChair(s): Ji-FengXu
LimCheeWah
GS2:ComputationalMechanics
Chair(s): Jia-LiangLe
MS4:ComputerVision-basedStudiesinStructuralHealthMonitoring
Chair(s): MohammadJahanshahi
16:25--16:40
A0195:InteractionsBetweenTopologicalDefectNucleationandBoundary
BranchingintheGrowthofCurvedCrystals
A0016(Invited):Output-OnlyIdentificationof
CivilEngineeringSystems
A0925(Invited):Strengthening,FailureandTwinningMechanismsof
Graphene/CopperComposites
A0063:ModelReductionTechniquesforDynamicSystemswithaLarge
NumberofLocalModes
A0372:SystemIdentificationandSeismic
ResponseMonitoringofLarge-ScaleBridgeModelsUsing
Target-TrackingDigitalImageCorrelation
LongMa Xiao-ShuZeng MohamedMoustafa
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16:40--16:55
A0318:TheAmplitude-Frequency
ResponseofThinCompositePlateintheThermal
Environment
A0016(Invited):Output-OnlyIdentificationof
CivilEngineeringSystems
A0925(Invited):Strengthening,FailureandTwinningMechanismsof
Graphene/CopperComposites
A0102:Group-TheoreticExploitationsof
SymmetryinComputationalMechanicsofNovelPrestressed
Structures
A0387:AutomaticBoltLooseDetection
basedonDigitalImageProcessingTechnology
Jin-MingLi ErtugrulTaciroglu NingHu YaoChen Lin-ShengHuo
16:55--17:10
A0174:ModelingandSimulationofthe
Electro-MechanicalCouplingBehaviorofLiquidCrystal
Elastomers
A0883:DynamicTestingofaFull-Scale
FRP-RetrofittedReinforcedConcreteBuildingFrame
A0776:ClassificationofSteelH-ShapedCross-SectionsunderCombined
CompressionandBendingConsideringPlateInteraction
Effect
A0629:ImplementationofaMesh
Sensitive-LessApproachforthePseudo-LowerBoundMethod
A0910:AnAlgorithmforIdentificationof
StructuralParametersandExcitationForcesUsing
NoncontactVision-basedDisplacementMeasurements
Yi-WeiXu JiukShin Xue-SongHou MicheleDeFilippo YingLei
17:10--17:25
A0069:OntheWrinklingand
RestabilizationofHighlyStretchedRectangularSheets
A0530:SimplifiedModelbasedonSpectrumAnalysisforthe
OptimalOutriggerLocationofHigh-RiseBuildings
A0247:Hazard-IndependentStudyofthe
StabilitySensitivityoftheLowRiseFrameSystemsSubjectedtotheExtremeLoadingConditions
A0661:MechanicalPropertiesof
FilamentousNetworksinTermsofTheirMicrostructure
TingWang Li-LiXing ChristopherL.Mullen HamedHatami-Marbini
17:25--17:40
A0216:CurvatureEffectonWrinklingandRestabilizationofHighly
StretchedElasticShells
A0851:MultiscaleRandomFields-based
DamageModelingandAnalysisofConcreteStructures
A0875:BucklingofCompositePlateswithReinforcedOvalHoles
A0211:WeakEnforcementof
DisplacementConditionsinFictitiousDomainFiniteElement
Analysis
Yi-FanYang HaoZhou Ling-Weitang Kai-ZhouLu
17:40--17:55
A0990:TheoryandVerificationforCalculationofGirderBridge
OverturningwithCouplingofRigidandDeformableBody
Rotation
A0705:SoilArchingEffectBasedStudyontheStressDistributionandFailureModeoftheHolesforUnder-ExcavationinBuilding
Rectifying
A0031:ComputationApplicationDevelopmentinScientific
Paradigm
Wei-BingPeng Qing-XiaYue EchefuFrancisEmeka
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17:55--18:10
A0024:AnalysisoftheBridgewithSingle
ColumnbyPerformanceandReliability-basedSeismicDesign
Method
A0188:EffectofPowerTake-offDampingonHydrodynamicEfficiencyofan
OscillatingWaterColumnWaveEnergyDevice
Yi-QiangXiang PiyushMohapatra
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PlenaryLectures
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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ZdeněkP.Bažant
Born and educated in Prague (Ph.D. 1963), Bažant joined Northwestern in
1969, where he has been W.P. Murphy Professor since 1990 and
simultaneously McCormick Institute Professor since 2002, and Director of
CenterforGeomaterials(1981-87).HewasinductedtoNAS,NAE,Am.Acad.of
Arts&Sci.,RoyalSoc.London;totheacademiesofItaly(lincei),Austria,Spain,
CzechRep., IndiaandLombardy; toAcademiaEuropaea,Eur.Acad.ofSci.&
Arts. Honorary Member of: ASCE, ASME, ACI, RILEM; received 7 honorary
doctorates (Prague, Karlsruhe, Colorado, Milan, Lyon, Vienna, Ohio State);
AustrianCrossofHonorforScienceandArt1stClassfromPresidentofAustria;ASMEMedal,ASME
Timoshenko,NadaiandWarnerMedals;ASCEvonKarman,Freudenthal,Newmark,Biot,Mindlin
andCroesMedalsandLifetimeAchievementAward;SESPragerMedal;RILEML’HermiteMedal;
ExnerMedal(Austria);TorrojaMedal(Madrid);etc.Heauthoredeightbooks:ScalingofStructural
Strength, Inelastic Analysis, Fracture & Size Effect, Stability of Structures, Concrete at High
Temperatures, Concrete Creep and Probabilistic Quasibrittle Strength. H-index: 121, citations:
66,000(onGoogle, incl.self-cit.), i10 index:605. In2015,ASCEestablishedZPBažantMedal for
FailureandDamagePrevention.Heisoneoftheoriginaltop100ISIHighlyCitedScientistsinEngrg.
(www.ISIhighlycited.com).His1959mass-producedpatentofsafetyskibindingisexhibitedinNew
EnglandSkiMuseum.
Home:http://cee.northwestern.edu/people/bazant/
DesignofNewMaterialsandStructurestoMaximizeStrengthatProbabilityTail:A
NeglectedChallengeforQuasibrittleandBiomimeticMaterials
ZdeněkP.Bažant
NorthwesternUniversity,USA
Abstract: In developing new materials, the research objective has been to maximize the mean
strength (or fracture energy) of material or structure and minimize the coefficient of variation.
However, for engineering structures such as airframes, bridges of microelectronic devices, the
objective should be to maximize the tail probability strength, which is defined as the strength
correspondingto failureprobability10-6per lifetime.Optimizing thestrengthandcoefficientof
variationdoesnotguaranteeit.Theratioofthedistanceofthetailpointfromthemeanstrengthto
thestandarddeviationdependsonthearchitectureandmicrostructureofthematerial(governing
thesafetyfactor)iswhatshouldalsobeminimized.FortheGaussianandWeibulldistributionsof
strength, theonlyonesknownuptothe1980s, thisratiodiffersbyalmost2:1.For thestrength
distributions of quasibrittle materials, it can be anywhere in between, depending on material
architecture and structure size. These materials, characterized by a nonnegligible size of the
fractureprocesszone,includeconcretes,rocks,toughceramics,fibercomposites,stiffsoils,seaice,
snow slabs, rigid foams, bone, dental materials, many bio-materials and most materials on the
micrometerscale.Atheorytodeducethestrengthdistributiontailfromatomisticcrackjumpsand
Kramer’sruleoftransitionratetheory,anddetermineanalyticallythemultiscaletransitiontothe
representativevolumeelement(RVE)ofmaterial,isbrieflyreviewed.Thestrengthdistributionof
quasibrittleparticulateorfibrousmaterials,whosesizeisproportionaltothenumberofRVEs,is
obtainedfromtheweakest-linkchainwithafinitenumberoflinks,andischaracterizedbyaGauss-
Weibullgrafteddistribution.Closeagreementwiththeobservedstrengthhistogramsandsizeeffect
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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curves are demonstrated. Discussion then turns to new results on biomimetic imbricated (or
scattered) lamellarsystems,exemplifiedbynacre,whosemeanstrengthexceeds thestrengthof
constituentsbyanorderofmagnitude.Thenacreousquasibrittlematerialissimplifiedasafishnet
pulled diagonally, which is shown to be amenable to an analytical solution of the strength
probability distribution. The solution is verified by million Monte-Carlo simulations for each of
fishnetsofvariousshapesand sizes. Inaddition to the weakest-linkmodeland the fiber-bundle
model, the fishnet is shown to be the third strength probability model that is amenable to an
analyticalsolution. It is foundthat,aside fromitswell-knownbenefit for themeanstrength, the
nacreousmicrostructureprovidesasignificantadditionalstrengtheningatthestrengthprobability
tail.Finallyitisemphasizedthatthemostimportantconsequenceofthequasibrittleness,andalso
themosteffectivewayofcalibratingthetail,isthesizeeffectonmeanstructuralstrength.
Engineering Mechanics Institute
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HerbertMang
Born:January5,1942,Vienna,Austria;Dipl.-Ing.,CivilEngineering,and Dr.techn., Vienna University of Technology (VUT) (1967 and1970); University Assistant, VUT (1967-79); Fulbright Fellow(1971-72), Research Assistant (1973), Ph.D. (1974), all at TexasTech;MaxKadeFellow,CornellUniversity(1975-76);Habilitation,VUT (1977); Visiting Research Associate, University of Tokyo(1979);AssociateProfessor,VUT(1979-83);UNIDOFieldExpert,Zhengzhou Research Institute for Mechanical Engineering, China(1981);Prof.,HeadofInstituteforMechanicsofMaterialsandStructures,VUT(1983-2010);Prof.Emer.,VUT(10-2010-);NationalRPGEChairProf.,TongjiUniv.,Shanghai(2012-);Co-authorof8booksand4chaptersofhandbooks,co-editorof16books,author(co-author)of226journalpapersand 280 proceedings papers, book chapters, etc.; 12 International/Foreign Prizes (including 2Foreign Decorations) and 12 National Prizes (including 3 Young Investigator Awards and 4Decorations); 6 Honorary Doctorates (Technical University of Cracow, Innsbruck, Kiev, Leoben,Prague,andVilnius);1HonoraryProfessorship,TongjiUniversity,Shanghai;ForeignAssoc.ofCAEandNAE;Memberof3EuropeanAcademiesofSciences(andArts)andof15National/RegionalAcademies of Sciences/ Engineering (in Austria, Croatia, the Czech Republic, Georgia, Germany,Hungary, Poland (Warsaw and Cracow), Portugal, Slovakia, in the Ukraine, and in the USA);President, Austrian Academy of Sciences (2003-06); Vice-President, Austrian Science Council(2010-2015).
MultiscaleAnalysisofConcreteStructures
AJointResearchProjectofTongjiUniversityandViennaUniversityofTechnology
HerbertMangViennaUniversityofTechnology,Vienna
TongjiUniversity,P.R.China
Abstract: ThepapercontainsareportaboutajointresearchprojectofTongjiUniversityandViennaUniversityofTechnology.Itstitlereadsas“BridgingtheGapbyMeansofMultiscaleAnalysis”.Theprojectwasinspiredbythetunnel,bridgingthegapbetweenthetwopartsoftheHongkong-Zhuhai-MacaoBridge(HZMB),bridgingthegapbetweencitiesonoppositesidesofthemouthofthePearlRiver into the South Chinese Sea. The project stretches over the time period 2015-2019. It isfinanciallysupportedbytheAustrianScienceFundandtheChinaScholarshipCouncil.Theaimoftheprojectisanassessmentoftheaddedvalueofmultiscaleanalysisoftunnelsegmentsbymeansofacomparisonofresultswiththeonesfromexperimentaltestsandwithresultsfromconventionalstructuralanalysis.Thefollowingfourtopicswillbetreatedinthelecture:(1) microstructuralanalysisofimpactandblastloadingoftunnellinings(2) multiscaleanalysisofthermalstressesincementliningsduetosuddentemperaturechanges(3) experiments and finite element modeling of concrete in Mechanized Tunneling with special
emphasisonconcretehinges(4) experimentallysupportedmultiscalestructuralanalysisofasegmentaltunnelringTheprojecthas convincinglyprovedtheaddedvalueofmultiscalestructuralanalysis, underlinedtheimportanceofbothmaterialtestsandlarge-scalestructuralexperimentsand,
lastbutnotleast, enabled participation of highly qualified students from both Tongji University and Vienna
UniversityofTechnologyinchallengingresearchworkintheframeworkoftheirdoctoralthesis.Itisagoodexampleofameaningfulblendofmaterialmechanicsofconcreteandmultiscaleanalysisofconcretestructures.
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Hai-YanHu
Prof.HaiyanHureceivedPh.D.inSolidMechanicsfromNanjingUniversityof
AeronauticsandAstronautics(NUAA),Chinain1988.Then,hewasaHumboldt
ResearcherFellowatUniversityofStuttgart,GermanyandaVisitingProfessor
atDukeUniversity,USAsuccessively.HereceivedProfessorshipinMechanics
in NUAA in 1994, served as President of NUAA from 2001 to 2007, and
PresidentofBeijingInstituteofTechnologyfrom2007to2017.
Prof. Hu has made recognized contributions to the nonlinear dynamics and
controlofaerospacestructures,includingthedelayedcontrolofflexiblestructures,thenonlinear
vibration isolation of missile stabilizers, the active flutter suppression of aircraft wings, and the
deploymentdynamicsofspaceantennas.HewaselectedFellowofTheChineseAcademyofSciences
in2007,FellowofTheWorldAcademyofSciences(TWAS)in2010,andawardedHonoraryDoctor
ofSciencebyMoscowStateUniversity,Russiain2015andbyUniversityofReading,UKin2016,
respectively.
EngineeringDynamicsofSoftMachines
HaiyanHu
BeijingInstituteofTechnology,P.R.China
Abstract:Theconceptofsoftmachinescoversagreatvarietyofadvancedindustrialproducts,such
asasoftrobothandlingfragileobjects,adeployablesolarsailandanairplanewithmorphingwings.
Thosesoftmachinesaremainlycomposedofsoftbodies,whicharemadeofsoftmaterials,including
polyimide,siliconelastomerandelectro-activepolymer,soastoadapttocomplexenvironmentsor
missions. Furthermore, the soft bodies undergo not only large deformations, but also overall
motionsandfrictionalcontactswiththemselvesortheirenvironments.
This lecture presents the dynamic study on soft machines in the frame of multibody system
dynamics.Thestudyfocusesontheefficientdynamicmodelingofthegeometricalnonlinearityof
coupledoverallmotionand largedeformationofasoftbody, thephysicalnonlinearityofhyper-
elasticity and elasto-plasticity, and interactional nonlinearity of frictional contacts or even
entanglementsofsoftbodies,aswellastheefficientdynamiccomputationalgorithmofrigid-soft
multibodysystemgovernedbyasetofdifferential-algebraicequationsofveryhighdimensions.The
lecture illustrates the proposed approach via three case studies, i.e., the locomotion of a soft
quadrupedalrobot,thespinningdeploymentofasolarsailofspacecraft,andthedeploymentofa
meshreflectorofsatelliteantenna,aswellasthecorrespondingexperimentalstudies.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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Jiun-Shyan(JS)Chen
J. S. Chen is currently the Inaugural William Prager Chair Professor of
Structural Engineering Department and the Director of Center for Extreme
EventsResearchatUCSanDiego.BeforejoiningUCSDinOctober2013,hewas
the Chancellor’s Professor of UCLA Civil & Environmental Engineering
DepartmentwhereheservedastheDepartmentChairduring2007-2012.J.S.
Chen’s research is in computational mechanics and multiscale materials
modelingwithspecializationinthedevelopmentofmeshfreemethods.Heis
thePastPresidentofUSAssociationforComputationalMechanics(USACM)andthePastPresentof
ASCE Engineering Mechanics Institute (EMI). He has received numerous awards, including the
Computational Mechanics Award from International Association for Computational Mechanics
(IACM), ICACE Award from International Chinese Association for Computational Mechanics
(ICACM),theTedBelytschkoAppliedMechanicsAwardfromASMEAppliedMechanicsDivision,the
BelytschkoMedal,U.S.AssociationforComputationalMechanics(USACM),amongothers.Heisthe
FellowofUSACM,IACM,ASME,EMI,ICACM,andICCEES.
MeshfreeMethods:ProgressMadeAfter20YearsandFutureDirections
Jiun-Shyan(JS)Chen
UniversityofCalifornian,SanDiego,USA
Abstract: In the past two decades, meshfree methods have emerged into a new class of
computationalmethodswithconsiderablesuccess.Inaddition,asignificantamountofprogresshas
beenmadeinaddressingthemajorshortcomingsthatwerepresentinthesemethodsattheearly
stages of their development. For instance, essential boundary conditions are almost trivial to
enforcebyemployingthetechniquesnowavailable,andtheneedforhighorderquadraturehas
been circumvented with the development of advanced techniques, essentially eliminating the
previouslyexistingbottleneckofcomputationalexpense inmeshfreemethods.Given theproper
treatment,nodalintegrationcanbemadeaccurateandfreeofspatialinstability,makingitpossible
to eliminate the need for a mesh entirely. Meshfree collocation methods have also undergone
significantdevelopment,whichalsoofferatrulymeshfreesolution.Thispresentationwillgivean
overviewofmajorprogressesmadeinthefield,theapplicationtomanychallengingengineering
mechanicsproblems,andthefuturedirectionsofthisresearcharea.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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Jin-GuangTENG
ProfessorJin-GuangTengisaVice-PresidentofSouthernUniversityofScience
andTechnology(SUSTech)andaChairProfessoratbothSUSTechandTheHong
KongPolytechnicUniversity(fractionalappointment).HeisanAcademicianof
the Chinese Academy of Sciences, a Fellow of the Hong Kong Academy of
Engineering Sciences and a Corresponding Fellow of the Royal Society of
Edinburgh.
Professor Teng has conducted research on a wide range of topics across the
broadfieldofstructuralengineering,includingthestructuraluseoffibre-reinforcedpolymer(FRP)
composites in construction as well as steel and thin-walled structures. He has authored/co-
authoredover200SCIjournalpapers,leadingtoover9,500citationsandanH-indexof50according
totheWebofScienceCoreCollection.Manyofhisresearchfindingshavebeenadoptedbyrelevant
designcodes/guidelinesinChina,Australia,Europe,theUnitedKingdomandtheUnitedStates.His
research contributions have been recognized by many awards and prizes, including the State
Natural Science Award of China, Distinguished Young Scholar Award from the National Natural
ScienceFoundationofChina,theIIFCMedalfromtheInternationalInstituteforFRPinConstruction
(IIFC), and the State-of-the-Art of Civil Engineering Award from the American Society of Civil
Engineers.
MechanicsofinterfacesinFRP-strengthenedstructures
Jin-GuangTENG
SouthernUniversityofScienceandTechnology,China
Abstract: The performance of structures, particularly concrete structures, can be substantially
enhanced through the external bonding of fiber-reinforced polymer (FRP) reinforcement in the
form of thin laminates. In such an FRP-strengthened structure, the interface between the FRP
laminateandtheexistingstructureplaysakeyroleindeterminingitsbehaviorandstrength.Indeed,
extensivelaboratorytestinghasdemonstratedthatfailureofFRP-strengthenedstructuralmembers
oftenoccursbydebondingoftheFRPlaminatefromtheexistingstructuralmemberinanumberof
distinctmodes.Inthispresentation,thespeakerwillprovideabriefreviewoftheintensiveresearch
undertakenoverthepasttwodecadesonthesedebondingfailureproblemsandasummaryofthe
currentunderstandingofinterfacialmechanicsinFRP-strengthenedstructuralmembersthathas
resultedfromthisresearch.Themajorpartofthepresentationwillbeconcernedwithinterfacesin
FRP-strengthenedconcretemembers,butinterfacesinFRP-strengthenedsteelmemberswillalso
be given due attention. The specific aspects to be covered include: (1) fundamental behavior of
bondedinterfaces;(2)classificationofdebondingfailuremodes;(3)debondingfailuremechanisms
and processes; (4) finite element and theoretical modelling issues; (5) design methods. The
presentationwillendwithabriefdiscussionoffutureresearchneeds.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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LoriGraham-Brady
Lori Graham-Brady is Professor and Chair of the Civil Engineering
Department at Johns Hopkins University, with secondary
appointments in Mechanical Engineering and Materials Science &
Engineering.SheisalsotheAssociateDirectoroftheHopkinsExtreme
Materials Institute. Her research interests are in computational
stochasticmechanics,multiscalemodelingofmaterialswithrandom
microstructureandthemechanicsoffailureunderhigh-rateloading.
ShehasbeenheavilyinvolvedinEMI,asamemberoftheEMIBoardofGovernors,asanAssociate
EditorfortheJournalofEngineeringMechanics,andastheChairoftheEMIProbabilisticMethods
Committee.Shehasreceivedanumberofawards,includingthePresidentialEarlyCareerAwardfor
ScientistsandEngineers(PECASE),theWalterL.HuberCivilEngineeringResearchPrize,andthe
WilliamH.HugginsAwardforExcellenceinTeaching.
Uncertaintypropagationfrommaterialscharacterizationtomodeling
LoriGraham-Brady
JohnsHopkinsUniversity,USA
Abstract: Three-dimensional microstructures collected by experimental characterization provide
both statistical information and the basis for computational models, which allows us to analyze
heterogeneousmaterialsatsmalllengthscales.However,thecollectionofsuchthree-dimensional
microstructuraldatacommonlyreliesondestructivetechniques,suchasserialsectioning,andsuch
methods often provide no quantitative measure of the accuracy of the digital microstructure in
representingthetruephysicalspecimen.Thismakesqualityassessmentofthedatasetsdifficult
and it poses a challenge to identify which characterization parameters will produce optimal
efficiency in the data collection process while maintaining an acceptable level of error in the
resultingdata.Toaddressthisquestion,thispresentationdescribesacomputationalmethodthat
wasdevelopedtosimulateserialsectioningdatacollection,basedonadigitalrepresentationofa
material,calledaphantom.Bysimulatingthedatacollectionanddataprocessingprotocolsofuser
definedparameterssuchasresolution,slicethickness,dwelltime,polishingmethod,etc.theeffect
ofeachonerrorpropagationcanbetrackedrelativetothefullyunderstooddigitalphantom.Then
byvaryingeachparametertheeffectscanbestudiedindividuallyandprovideboundsonboththe
contributions of each parameter to the error as well as the total error introduced through the
experimental process. This provides a quantitative method for comparing the relative trade off
betweenexperimentalparameterssuchcollectingdataataveryhighresolutionvs.collectingdata
overalargevolume.Ultimatelythesemeasuresarethenutilizedaspartofanobjectivefunctionto
optimize the selection of experimental parameters. An example of optimization of experimental
datacollectionparametersfortheacquisitionofan3DElectronBackscatterDiffraction(EBSD)data
setdemonstrateshowtheerrorincomputationalmodelscanbereduced.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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Abstracts
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS1: Cementitious Materials: Experiments and
Modeling across the Scales
A0013- Road guard innovative use of plastic waste material in redesigning road
curbs
AhiatiEbenezera
aStudent,KwameNkrumahUniversityofScienceandTechnology,
TherearemanydeterioratedroadsinGhana,WestAfrica.Thesedeteriorationsmostlyoccur
duetoerosionfromrainfallandcauseseveraldepressionsinroads,mostlyalongtheedges.
Thiscanhaveadverseeffects,suchasaccidents.Analternativetoprotectingroadedgesafter
construction is the use curbs. However, traditional curbs are expensive and using them as
means of protection for a road system is not feasible. Hence, this paper introduces a cost
effective and reliable approach of using a polymer-based product molded into grids, Road
Guard, since reconstruction of roads after a short while of usage is too expensive for a
developingcountry.TheRoadGuardwillbeproducedfromrecyclingplasticwaste,whichis
anothermajorprobleminthecountry,andwillbeconvertedintogridsthroughmeltingand
casting.Itwillhaveanarbitrarylengthof20.669feet(6.3meters)withachannelatabout
every19.029feet(5.8meters)toallowforrainwaterrun-offs.Installationwillbecarriedout
byplacingtheroadguardat theedgesof theroadandfilling itwiththeroadconstruction
material (concrete, bitumen, etc.) before, during or after road construction. After a cost
analysis it was obtained that equivalent length of Road Guard compared to the curbs was
cheaper.Apartfromsolvingtheissuewiththeroads,theplasticwastemenaceinthecountry
willalsobeaddressedsincetheywillbeusedtoproducethedevice.Inconcluding,theRoad
Guardisstill intheconceptualstagesandhenceneedsalotoftesting.However,onemajor
setbackisthelackoffundingtoproduceaworkingmodeleventhoughaprototypehasbeen
producedfromcardboardforsubsequentinstallationtests.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0028-Performanceoftheconcretefreefromsteelreinforcement
YUJiangtaoa,YeJunhongb,ZHANKailic
aCollegeofCivilEngineering,TongjiUniversity,ShanghaiChina,email:
bCollegeofCivilEngineering,TongjiUniversity,ShanghaiChina
cCollegeofCivilEngineering,TongjiUniversity,ShanghaiChina
Ultra-high ductility cementitious composites (UHDCC) developed by the authors has the
tensilestraincapacityclosetothatofsteel.ToexplorethefeasibilityofusingplainUHDCCin
construction, a series of experiments were conducted at material, structural member and
structure scales, including mechanical properties of UHDCC, the behavior of plain UHDCC
beams and columns under monotonic and lateral cyclic loadings, and the responses of
compositeUHDCCframeundervariousearthquakeexcitations.Thetestresultsindicatedthat
the average tensile strain capacity of UHDCCs reached 12%, exceeding the strain capacity
required forsteelusedtoreinforceconcretestructure.Additionally,UHDCCevenexhibited
strain-hardeningcharacteristicsundercompression.Theresultsfromfour-pointbendingtest
demonstratedtheoutstandingperformanceofUHDCCbeamsunderlateralcyclicloading.The
plainUHDCCbeamhascloseloadbearingcapacitytothereferenceRCbeamswiththesteel
reinforcementratioof1.0%butmuchbetterflexuralductility.RCframe(reinforcementratios
ofcolumnswereabout2.0%)andplainUHDCCframewerecomparativelytestedonashaking
table.TheplainUHDCCframesurvivedaseriesofseismicexcitationswiththepeakground
accelerationrangingfrom0.105gto1.178g,andexhibitedbetterenergy-dissipatingcapacity
associated with consistently increasing damping ratio under earthquake excitations. The
performanceoftheplainUHDCCframefulfilledtherequirementsinChineseseismiccode,i.e.,
no damage under the frequently occurring earthquake, being repairable under the design-
based earthquake, and no collapse under the rarely occurring earthquake. Generally, this
seriesstudyfrommaterialscaletostructurescaleconfirmedthefeasibilityofconstruction
withplainUHDCC.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0038- Macro-scale strength and microstructure of ZrW2O8 cementitious
compositeswithtunablelowthermalexpansion
OuyangJianshua,YangboLib,BoChenc,DahaiHuangd
aSchoolofTransportationScienceandEngineering,BeihangUniversity,Beijing,China
bCollegeofHydraulicandEnvironmentalEngineering,ChinaThreeGorgesUniversity,
YichangHubei,China,email:[email protected]
cCollegeofHydraulicandEnvironmentalEngineering,ChinaThreeGorgesUniversity,
YichangHubei,China
dSchoolofTransportationScienceandEngineering,BeihangUniversity,Beijing,China
Concretes with engineered thermal expansion coefficients, capable of avoiding failure or
irreversible destruction of structures or devices, are important for civil engineering
applications, such as dams, bridges and buildings. In natural materials, thermal expansion
usuallycannotbeeasilyregulatedandanextremelylowthermalexpansioncoefficient(TEC)
is still uncommon. Here we propose a novel cementitious composite, doped with ZrW2O8,
showingawiderangeoftunablethermalexpansioncoefficientfrom8.65×10-6℃-1to2.48×10-
6℃-1. Macro-scale experiments are implemented to quantify the evolution of the thermal
expansioncoefficients,compressiveandflexuralstrengthoverawiderangeoftemperature.
Scanning Electron Microscope(SEM) imaging was conducted to quantify the specimens’
microstructuralcharacteristicsincludingporesratioandsize.ItisshownthattheTECofthe
proposed composites depends on the proportion of ZrW2O8 and the ambient curing
temperature.Macro-scaleexperimentalresultsandmicrostructureshaveagoodagreement.
TheTECandstrengthgraduallydecreaseasZrW2O8increasesfrom0%to20%,subsequently
fluctuatesuntil60%.Thefindingsreportedhereprovideanewroutinetodesigncementitious
compositeswithtunablethermalexpansionforawiderangeofengineeringapplications.
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A0139-Strengtheningeffectofcementitiousmaterialssubjectedtohigh-dynamic
loading
E.Bindera,Y.Yuanb,H.Mangc,B.Pichlerd
aPhDcandidate,InstituteforMechanicsofMaterialsandStructures,TUWien–Vienna
UniversityofTechnology,Austria,Europe,[email protected]
bProfessor,CollegeofCivilEngineering,TongjiUniversity,Shanghai,People’sRepublicof
China,[email protected]
cProfessor,InstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversity
ofTechnologyAustria,Europe,andCollegeofCivilEngineering,TongjiUniversity,Shanghai,
People’sRepublicofChina,[email protected]
dProfessor,InstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversity
ofTechnology,Austria,Europe,[email protected]
The compressive strength of concrete increases with increasing speed of dynamic loading.
Fischeretal.developedanelasto-brittlemodeltoaccountforthisstrengtheningeffect.The
mainideaofthismodelisthatcracksnucleateassoonasthequasistaticstrengthisreached
andthathigh-dynamicstrengtheningmanifestsitselfintheincreaseofthecompressivestress
duringtheevolutionofthefailuremode.Fischeretal.corroboratedthepredictivecapabilities
ofthemodelbycomparingmodelpredictionswithexperimentaldatafromhigh-dynamictests
ofspecificcementpasteandmortarspecimens.Continuedexemplaryvalidationisthetopicof
the first part of this contribution. Model predictions are compared with additional
experimentaldatafromhigh-dynamictestsofspecificmortarandconcretecylinders.Inthe
secondpart,themodelofFischeretal.iscombinedwiththevalidatedmultiscalemodelfor
thequasi-staticcompressivestrengthofconcretebyKönigsbergeretal.,tostudytheinfluence
ofhardeningoftheconcreteusedfortheimmersedtunneloftheHongKong-Zhuhai-Macao-
Bridgeonitsdynamiccompressivestrength.Inthethirdpart,themodelisextendedtowards
considerationofthehigh-dynamictensilestrength.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0198- Multiscale modeling of cementitious materials: from hydration via
microstructuretomacroscopicproperties
BernhardPichlera,ChristianHellmichb
aAssociateProfessorandDirectoroftheLaboratoryforMacroscopicMaterialTesting,
InstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversityof
Technology,Austria,Europe,[email protected]
bFullProfessorandDirectoroftheInstituteforMechanicsofMaterialsandStructures,TU
Wien–ViennaUniversityofTechnology,Austria,Europe,[email protected]
The philosophy of multiscale modeling of heterogeneous materials is to resolve their
microstructure,inastep-by-stepfashion,downtoascaleatwhichmaterialconstituentsare
foundthatexhibitmaterialconstantsratherthanevolvingmaterialparameters.Concrete,for
instance,isamatrix-inclusioncomposite,withaggregatesandsandrepresentinginclusions
which are embedded in a cement paste matrix. The properties of cement paste are not
constant,becausetheydependon itscompositionandmaturity, i.e.onthe initialwater-to-
cementmassratioandthedegreeofhydration.Thus,cementpasteismodeledasamatrix-
inclusion composite, with residual cement particles representing inclusions which are
embeddedinahydratefoammatrix.Thehydratefoamisahighlyrandomizedarrangementof
capillary pores (which are filled either by water or air) and hydration products which are
needle-shaped and isotropically-oriented in space. As for the hydration products, material
constantscanbeintroduced,whichallowforpredictionofthehydration-drivenevolutionsof
stiffness,creep,andstrengthofcementitiousmaterials.Thepresentcontributionprovidesan
overviewoverrelatedmultiscalemodelingactivitiescarriedoutattheInstituteforMechanics
of Materials and Structures at TU Wien – Vienna University of Technology. Concretes are
considered to consist of aggregates, sand, cement, water, air, and hydration products. The
latterarethe“glue”ofthemicrostructure,theonlycreepingconstituent,andtheweakestlinks
ofthemicrostructureofcementitiousmaterials.Thus,theyareessentialforthemacroscopic
stiffness, creep, and strength of cementitious materials. Eshelby-problem-based
homogenization schemes of continuum micromechanics allow for bridging all the scales
between the hydration products and the macroscopic application scale of cementitious
materials. It can be shown that the behavior of hydration products is governed by simple
physical laws. The latter translate, because of microstructural interactions with other
constituents,intoacomplexmacroscopicbehaviorofcementitiousmaterials.
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A0244- Investigation of the shrinkage - volume to surface ratio relationship in
cementconsideringcracking
Y.Zhanga,M.H.Hublerb
aResearchAssistant,UniversityofColorado,Boulder,[email protected]
bAssistantProfessor,UniversityofColorado,Boulder,[email protected]
Standardized shrinkage models for concrete incorporate a function which depends on the
volumetosamplesurfaceratio(V/S).This functionstemsfromexperimentalobservations
andhasbeenrationalizedbasedonnon-uniformporehumiditydistributionsduringdrying,
whichdependonV/S.Suchshrinkagestressdistributionsshouldalsoleadtodifferentcrack
developmentasafunctionofV/S.Byconductingcompanion3DX-rayMicroscope(XRM)scans
andshrinkagestudiesofcementsofdifferentV/Sratios,theimpactofcrackdevelopmenton
thissizeeffectrelationshipisstudied.TheXRMscanscanresolvedryingcontourstovalidate
computed pore humidity distributions. Furthermore, the scanned internal surface area
(incorporatingporesandcracks)providesamoreaccuraterepresentationofdryingsurface.
Byintegratingtheinternalsurfaceareaintothecomputedporehumditydistributions, it is
possible to understand how cracking and porosity play a role in the shrinkage to V/S
relationship.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0278-DynamicpropertyidentificationofshakingtabletestaboutexistingR.C
CHENGShaogea,SUNKuib
aResearcher,ChinaAcademyofBuildingResearch,Instituteofearthquakeengineering,
bDoctoralstudent,ChinaAcademyofBuildingResearch,Instituteofearthquakeengineering,
Becauselowconnectionstrengthandhighstiffnessbetweeninfilledmasonrywallandframe,
the infilled would separate from major structure members or cracked in less earthquake
influence, then the dynamic properties of specimen had changed significantly. So that the
whitenoiseusedforspecimenhadasmallamplitude,andashortduration.Largedeviations
existedinfrequencydomainmethodathighfrequencies,indicatinglessaccuracyoffrequency
domainmethod.Systemidentificationofthespecimenwereextractedfromflooraccelerations
underthewhitenoiseexcitationsbytheeigensystemrealizationalgorithmmethodandnature
excitationtechnique .Dampingcharacteristicsof thespecimenwere identified. It isshown
that eigensystem realization algorithm method is effective and sensitive to higher modes
respectively. And it can identify the crack behavior of infilled masonry wall. High mode
vibrationiseasytooccurforexistingR.C.frame.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0283- Multiscale thermomechanical analysis of reinforced concrete beams
subjectedtosuddenheating
H.Wanga,Y.Yuanb,H.Mangc,B.Pichlerd
aInstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversityof
Technology,Austria,Europe,[email protected]
bCollegeofCivilEngineering,TongjiUniversity,Shanghai,People’sRepublicofChina,
cInstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversityof
Technology,Austria,Europe,[email protected]
dInstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversityof
Technology,Austria,Europe,[email protected]
Steel-reinforcedconcretestructuresaresubjectedtosuddentemperaturechanges,e.g.,inthe
exceptional load case of a fire. At the macrostructural scale, kinematic constraints are
hinderingthedeformationsassociatedwiththethermaleigenstrains.Thus,thermalstresses
areinduced.Theconstraintsoriginatefromthreesources:thesupportconditionsofstatically
indeterminatestructures,thegeometricincompatibilityofmacroscopiceigenstrainsresulting
fromnon-stationaryheatconduction,andthemismatchofthermalexpansioncoefficientsof
the steel and the concrete. At the microstructural scale of plain concrete, self-equilibrated
stresses prevail even in the absence of macroscopic kinematic constraints. These stresses
resultfromthemismatchofthethermalexpansioncoefficientsofthecementpasteandthe
aggregates.Thepresentcontributionisinspiredbyapotentialfireinsidetheimmersedtunnel
oftheHongKong-Zuhai-Macao-Bridge.Theoverheadslabsofthesegmentsofthetunnelare
idealizedasreinforcedconcretebeams.Theirbottomsurfacesaresubjectedtosuddenheating.
Three-dimensionalanalysesprovideinsightintomacroscopicandmicroscopicstressstates.
Tothisend,modernmultiscalematerialmodelsforconcreteareusedtoquantifytheelastic
stiffnessandthethermalexpansioncoefficientoftheconcreteusedforthesegmentsofthe
aforementioned immersed tunnel. These macroscopic properties serve as input for
thermomechanical Finite Element simulations of the steel-reinforced concrete beams. The
obtained macroscopic temperature distributions and stress fields are postprocessed in the
contextoftop-downanalysiswhichallowsforquantifyingthemicroscopicaveragestresses
experienced by the cement paste and the aggregates. Two sources of microscopic stress
fluctuations are identified: macro-to-micro stress concentration, governed by stiffness
contrasts,andtheincompatibilityofthemicroscopicfieldsofthermaleigenstrains,governed
bythemismatchofthethermalexpansioncoefficientsofthecementpasteandtheaggregates.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0327- Influenceofsteel fibre,electricalwastecopper fibreandE-glass fibreon
mechanicalpropertiesofconcrete
A.Sofia,G.GaneshNaidub
aAssociateProfessor,DepartmentofStructuralandGeotechnicalEngineering,SchoolofCivil
Engineering,VITVellore,Tamilnadu,India,[email protected]
bResearchScholar,SchoolofCivilEngineering,VIT,Vellore,Tamilnadu,India
Fibre-reinforced concrete (FRC) contains fibrous material which increases its structural
integrity. The application of sporadic fibres to concrete altogether upgrades its essential
characteristics,forinstance,staticflexuralstrength,influencequality,elasticity,malleability
andflexuralstiffness.Filamentsareaddedtocementtocontrolbreakingbecauseofplastic
shrinkageandtodryingshrinkage.Thispaperexhibitstheuseofsteelfibre,electricalwaste
copperfibreandE-glassfibreofvariouspercentagesofvolumefractionssuchas0.25%,0.5%,
1%and1.25%incorporatedinconcrete.Mechanicalpropertiessuchascompressivestrength,
splittensilestrengthandflexuralstrengthtestswereconductedfornormalconcreteandfibre
reinforcedconcreteforacuringperiodof7days,14daysand28days. Inadditiontothat
modulusofelasticityofconcreteforvariouspercentagesoffibrecontentwascalculatedfora
curingperiodof28days.Thetestresultsof fibrereinforcedconcretewerecomparedwith
normalconcretetoobtaintheoptimumdosageoffibresused.
Engineering Mechanics Institute
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A0685- Effects of loading rates and temperatures on pullout responses of basalt
yarnandfabricembeddedincementitiousmatrix
SaiLiua,DejuZhub
aKeyLaboratoryforGreen&AdvancedCivilEngineeringMaterialsandApplication
TechnologyofHunanProvince,CollegeofCivilEngineering,HunanUniversity,Changsha,
China
bKeyLaboratoryforGreen&AdvancedCivilEngineeringMaterialsandApplication
TechnologyofHunanProvince,CollegeofCivilEngineering,HunanUniversity,Changsha,
China,[email protected]
Pullout response of basalt fabric embedded in cementitious matrix specimens was
investigatedunderdifferentloadingratesandtemperatures.Twotypesofpulloutspecimens,
namelybasaltsingleyarnandbasaltfabricweretested.Thepulloutbehaviorsofspecimens
wereevaluatedintermsofinitialpulloutforce,peakpulloutforce,workofpulloutandwork
ofpeakforce(Fig.1).Pulloutvelocityrangesfromstatic(5.0×10-5m/s)todynamic(1.0,2.0,
3.0and4.0m/s);Anddynamicresponseswerestudiedunderfourtemperatures(-25,0,25,
50̊ C)withdifferentloadingrates.Theexperimentalresultsindicatedthatthepulloutvelocity,
temperatureandthefabricformcansignificantlyaffectthepulloutresponses.Thereexista
typicalthreestagesduringpulloutloadings(Fig.1).Ateachtemperature,theinitialandpeak
pulloutforcesunderdynamicloadingarehigherthanthestaticones.Inaddition,thepullout
workandpeakpulloutworkappeartobeimprovedwithincreasingloadingrateundereach
temperature.Ontheotherhand,whenthepulloutvelocityisconstant,theinitialpulloutforce,
peak pullout force, work of pullout and work of peak force decreased with increasing
temperatures. While the pullout work and peak pullout work appear to be improved with
increasingpulloutvelocitiesundereachtemperature.
Fig.1.Schematicof(a)threestagesofthepulloutprocessand(b)definedparametersto
characterizethepulloutresponsesunderloading.
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A0691- Insight into the role of interfacial bolts on the structural behavior of
segmentaltunnelrings
J-L.Zhanga,H.A.Mangb,X.Liuc,Y.Yuand,B.Pichlere
aPhDstudent,DepartmentofGeotechnicalEngineering,TongjiUniversity,PRChina
bProf.,DepartmentofGeotechnicalEngineering,TongjiUniversity,PRChina
cProf.,DepartmentofGeotechnicalEngineering,TongjiUniversity,PRChina
dProf.,DepartmentofGeotechnicalEngineering,TongjiUniversity,PRChina
eProf.,InstituteforMechanicsofMaterialsandStructures,TUWien–ViennaUniversityof
Technology,Austria,Europe,[email protected]
Steelboltsarefrequentlyusedtoconnectneighboringsegmentsofsegmentaltunnelrings.
Oncetheboltsbecomeactiveintension,theyincreasethelocalbendingstiffnessandthelocal
bearingcapacityofthejoint.Inordertogainmoreinsightintotheroleofinterfacialboltson
theoverallstructuralbehaviorofsegmentaltunnelrings,structuralsensitivityanalysesoftwo
similartunnelrings,onewithunreinforced jointsandtheotheronewithbolted joints,are
carried out. They involve combining nonlinear interface models with transfer relations
representinganalyticalsolutionsofthegoverningequationsofthe lineartheoryofslender
circulararches.Thesensitivityanalysesrefertodeterminationoftheelasticlimitandofthe
bearingcapacityof the segmental tunnel ringssubjected togroundpressure.Theanalyses
haveshownthatinterfacialbolts(i)decreasetheelasticlimitintensityofgroundpressure,(ii)
improve the serviceability of segmental tunnel rings, because they ensure the position
stabilityofthelining,(iii)aremandatoryforoverallstructuralequilibriumincaseofmarkedly
anisotropicgroundpressure,and(iv)significantlyincreasethebearingcapacityofsegmental
tunnelrings. Inordertoverifytheseconclusions,real-scaletestsofthreetunnelrings,one
withoutinterfacialbolts,onewithnewbolts,andonewithcorrodedbolts,werecarriedout.
The experimental investigations have confirmed the conclusions listed above. This
corroboratestheusefulnessofthepresentedmodelforstructuralanalysisofsegmentaltunnel
ringsandprovidesthemotivationtoemployitforfuturestructuralanalysisaccountingfor
durabilityofinterfacialbolts.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0736-Meso-finiteelementfractureanasysisforfiberreinforcedemulsifiedasphalt
–cementconcrete
JunFua,TaoZhangb,ZhehanLaic
aAssociateProfessor,WuhanUniversityofTechnology,[email protected]
bMasterCandidate,WuhanUniversityofTechnology,[email protected]
cMasterCandidate,WuhanUniversityofTechnology,[email protected]
PVAfiberswasusedto improvethe flexural tensilestrengthandcrackresistance forFiber
Reinforced Emulsified Asphalt–Cement Concrete(FREACC). Three-point bending test and
uniaxialcompressiontestshowedthatPVAfibercouldsignificantlyimprovethemacroscopic
flexuraltensilestrengthandfractureenergyofthemixture,whichhadanincreasemorethan
100%and50%,buthadlittleeffectonthecompressivestrengthandelasticmodulus,which
hadanincreaseabout3%.Inmesoscale,FREACCcouldbeconsideredasthreephaseswhich
wereaggregates,fiber-asphaltcementmortar,andpores.Basedonthetwo-dimensionalimage
digitizationandbilinearcohesivezoneconstitutiverelation,themeso-finiteelementfracture
modelcouldbeestablishedbyinsertingtwo-dimensionalzero-thicknesscohesive interface
elementsintotheinterfacebetweendifferentphases.Uniaxialtensilefractureanddynamic
crackingofthree-pointbendingbeamweresimulated,thentheeffectofPVAfibersonfracture
toughness was discussed. The numerical simulation value of fracture energy was slightly
larger thantheexperimentalvalue,andthemeso-fractureanalysiswas ingoodagreement
withthemacroscopictestresults.Theresultsofmicrofractureanalysisalsodepictedthatthe
interfacebetweenaggregateandasphaltmortarwasaweakphase,wherethefracturestarted
fromtheinterface.AndPVAfibercouldeffectivelyenhancethetensilestrengthofthemixture
anddelaythecrackpropagation.Thecriticalfractureloadandthecorrespondingmid-span
displacement of meso-numerical simulation were slightly smaller than the experimental
values,butthedifferenceoftensilestrengthwasnotobvious.Thenumericalsimulationvalue
of fracture energy was slightly larger than the experimental value, but the meso-fracture
analysiswasingoodagreementwiththemacroscopictestresults,demonstratingthatthetwo-
dimensionalmeso-fracturemodelwasrelativelyaccurateunderuniaxialloadingandthree-
pointbendingconditions.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
45
A0761- Time-space dependent stability analysis of shallow natm tunnels with
discontinuitylayoutoptimization
Yiming.Zhanga,Xiaoying.Zhuangb,c,Roman.Lacknerd
aSchoolofCivilandTransportationEngineering,HebeiUniversityofTechnology,Tianjin,
China,[email protected]
bDepartmentofGeotechnicalEngineering,TongjiUniversity,Shanghai,China,
cInstituteofContinuumMechanics,LeibnizUniversitätHannover,Hannover,Germany
dMaterial‐TechnologyInnsbruck(MTI),UniversityofInnsbruck,Innsbruck,6020,Austria,
Shallow tunnels constructed by New Austrian Tunnelling Method potentially experience
stability problems caused by inappropriate excavation speed or supporting procedures.
Stabilityofthesectionsofthesetunnelsaretime-spacedependent,referringtothehydration
processesofshotcrete,shapesofthetunnelsandexcavationspeed.
Inthiswork,weimplementthemultiscalemodelofhydratingshotcreteintotheframeworkof
discontinuitylayoutoptimization,whichiscapableofefficientlyobtainingthefactorofsafety
and the corresponding failure mechanism of tunnel section. Meanwhile, convergence-
confinementmethodisusedforaccountingthe3-dimensionaleffectin2-dimensionalanalysis,
providingtime-spacedependentstabilityassessmentsofthesetunnels.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
46
A0887-MechanicalperformanceofGFRPsandwichpanelswithstiffenwebs
FangMing-Jia,HouHetaob,WangWenhaoc
aSchoolofCivilEngineering,ShanghaiNormalUniversity,Shanghai,P.R.China
bSchoolofCivilEngineering,ShandongUniversity,Jinan,P.R.China
cSchoolofCivilEngineering,ShandongUniversity,Jinan,P.R.China
Thispaperpresentsthedetailsofaresearchprogramthatwasconductedtoevaluatetheone-
waybendingbehaviorofglassfiberreinforcedpolymer(GFRP)sandwichpanels.Thepanels
consistofGFRPskinswithafoam-GFRPwebcore.Anexperimentalstudywerecarriedoutto
studytheeffectoftheskinandwebthickness,thewebheightandthewebspace.Theresults
demonstrate that compared to the only foam-core sandwich panels, a maximum of
approximately230%increaseintheultimatebendingstrengthcanbeachieved.Meanwhile,
thebendingstiffnessandenergydissipationcanbeenhancedrespectively.Acomparisonof
theexperimentalandanalyticalresultsshowedthattheanalyticalmodelaccuratelypredicted
the ultimate bending strengths deflections of the panels under four-point bending.
Furthermore, the finite element analysis was conducted to simulate the bending behavior
consideringthebondperformanceofthefacesheetsandfoamcore.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0919-Microstructuralcharacterizationofthespuncastconcrete
M.Sobótkaa,M.Pachniczb,J.Michałekc
aassistantprofessor,FacultyofCivilEngineering,WrocławUniversityofScienceand
Technology,[email protected]
bPhDstudent,FacultyofCivilEngineering,WrocławUniversityofScienceandTechnology,
cassistantprofessor,FacultyofCivilEngineering,WrocławUniversityofScienceand
Technology,[email protected]
Theaimoftheworkwastopreparetheprocedurefordeterminingselectedmicrostructure
propertiesofthespunconcretewithparticularemphasisonthevariationoftheseproperties
withthedistanceRfromtheouteredgeofthemember.Theresearchwascarriedoutusing
threedifferenttestingmethods:nanoindentation,X-raymicrocomputedtomography(mCT)
and 2D optical scanning. Obtained results allowed to characterize quantitatively following
features of concrete internal microstructure: the distribution of aggregate throughout the
member cross-section, the variability of mechanical parameters of the mortar with the
distanceRandthespatialdistributionofthepores.
TheanalysisofaggregatedistributiononthecoordinateRwasbasedontheresultsofoptical
scanning.Surfacepreparationof theconcretesamples forscanning includedgrinding,acid
etchingandmatrixdyeing.Aggregatesegmentationfromtheimageswasmadeusingdigital
imageprocessingtechniques.Morphometricanalysisincluded,amongothers,determination
ofthevolumefractionandlocalthicknessoftheaggregate.
Inordertodeterminethemechanicalparametersofthemortar(cementmatrixtogetherwith
fineaggregate), thenanoindentationmethodwasutilized.Aseriesof testswascarriedout
withCSM(AntonPaar)TTX-NHTapparatusequippedwithBerkovichtip.Severalmeasuring
gridsweresetwithinthemortaratarbitrarylocationscorrespondingtodifferentvaluesofR
distance. Each of the grids included 100 imprints spaced at 50 μm. The results of the
performedtestsallowedtoestimateaveragevaluesofthehardnessHITandtheindentation
modulusMIT.Furthermore,applyingdeconvolutionmethodallowedtoestimatethefraction
of the fine aggregate in mortar φ and to calculate the average hardness and average
indentationmodulusforthecementitiousmatrixandtheaggregateseparately.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
48
Theanalysisoftheporesdistributionthroughouttheconcretevolumewasbasedonthe3D
imagingbymCT.BrukerSkyscan1172scannerwasutilizedtoacquireasetofprojections.
ImagereconstructionwasperformedusingBrukerNReconsoftwarebasedontheFeldkamp
algorithm.SincethegrayscalevaluesinmCTdependmostlyonthematerialdensityonecan
assess the variation of average material density with the coordinate R. To characterize the
spatialarrangementofthepores,theywerefirstsegmentedbythresholding.Next,thebinary
imagesoftheporeswasanalyzed.Theporespacewaspresentedinathree-dimensionalmodel
andquantitativeanalysiswasperformed.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS2: Modeling Time-Dependent Behavior and
Deterioration of Concrete
A0042-Concretecreepmodeling:applicationtoslabsonground
YaWeia,SimingLiangb,JingsongHuangc
aM.ASEC,AssociateProfessor,DepartmentofCivilEngineering,TsinghuaUniversity,Beijing,
China,[email protected]
bPost-doc,DepartmentofCivilEngineering,TsinghuaUniversity,Beijing,China,
cMasterstudent,DepartmentofCivilEngineering,TsinghuaUniversity,Beijing,China,
Moisturewarpingofconcreteslaboccursasa longprocessdueto theslowtransportation
natureofmoisture inconcretematerials.And thuscreep,asa timedependentpropertyof
concrete,willinevitablyaffecttheperformanceofslabongroundduringthisprocess.Inthis
study, the effect of concrete creep is considered in pavement slab for analyzing moisture
warping, warping stress, and the total stress under traffic loads. A method is proposed to
calculatethetime-dependentwarpingdeformationandstressdevelopmentsinconcreteslab
onground.Thismethodusesthesequentialcoupledhygromechanicalfiniteelementanalysis
andincorporatesconcretecreepmodelwhichiscapableofconsideringtherelativehumidity
effect.Theeffectofenvironmentrelativehumidity,thedesignparameters,includingconcrete
type,slabsize,thickness,boundingconditionwiththebase,andtheageofconcreteexposed
todryingare investigatedontheslabwarpingandstressconsideringthecreepeffect. It is
found that concrete creep has a significant effect on slab warping and stresses. It is of
importancetoconsidercreepeffectindesignandanalyzingdeformationandstressgenerated
inconcretepavementslabs,particularlywhenamoisturegradientexistsinslab.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0082-NumericalmoduledevelopmentfortheentireprocessofRCdeterioration
duetonon-uniformcorrosion
This study presents a mathematical model to depict each sub-process of reinforcement
corrosion and their coupling effect based on the physical mechanisms of corrosion
electrochemical reaction. Then, a physical-chemical-electro-chemical-mechanical multi-
physicscoupledcomprehensivenumericalmoduleisdevelopedtosimulatetheentireprocess
ofthecorrosion-induceddeteriorationofRCstructure;andthereductionoftheload-carrying
capacityoftheRCstructureversusexposuretimecanbegivendirectly.Thedistributionof
corrosionproductsonthesurfaceofthesteelreinforcementwillbedeterminedautomatically,
withouthavingtobepresetinadvance.Topredicttheexpansionpressureofconcreteandthe
evolution of cracking pattern caused by non-uniform corrosion, a new smeared rust layer
method is first proposed here. Several sets of experimental data were compared with the
predictionbythenumericalmodelforitsverification.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0093-Concreteshearwallsaffectedbyalkali-silicareactionpartii:modeling
AncaC.Ferchea,ShamimA.Sheikhb,FrankJ.Vecchioc
aPhDCandidate,UniversityofToronto,[email protected]
bProfessor,UniversityofToronto,[email protected]
cProfessor,UniversityofToronto,[email protected]
Aprocedurefornonlinearanalysisofreinforcedconcretestructuresaffectedbyalkali-silica
reaction(ASR) is presented.Twodistinct time-dependentmechanismsareconsidered: the
magnitude of the expansion, and the deterioration in the mechanical properties of the
concrete. With these mechanisms implemented within the framework of finite-element
programs developed for the analysis of membrane and three-dimensional structures, a
smearedrotating-crackmacro-modelingapproachwasappliedtotheanalysisofASR-affected
shear walls tested under reversed-cyclic loading. The modeling techniques employed are
detailed, as well as the factors affecting the computed response of the specimens. The
sensitivitystudiescarriedout identifyseveralmechanismsthathadanotableeffectonthe
behavior.Basedontheresultspresentedherein,themodelingproceduresdescribedarefound
tobeusefulforthecapacityassessmentofdeterioratedshearwallsduetoASR.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0098-Concreteshearwallsaffectedbyalkali-silicareactionparti:testing
FarhadHabibia,FrankJ.Vecchiob,ShamimA.Sheikhc
aPhDCandidate,UniversityofToronto,[email protected]
bProfessor,UniversityofToronto
bProfessor,UniversityofToronto,[email protected]
ReactiveaggregateshavebeenusedinnuclearpowerplantstructuresinNorthAmericaand
elsewhere. Nuclear structures, in general, are heavily reinforced and often prestressed.
AlthoughASRhasbeenextensivelystudiedovertheyears,availableinformationontheeffects
ofASRonsuchstructuresislimited.
Theexperimentalstructuralpartofthisresearchprogramisfocusedontestingofreinforced
concrete walls made with ASR concrete and evaluating their performance against similar
controlwallsthatexcludereactiveaggregates.Atotalofsixwallswereconstructed,fourmade
with ASR concrete and two with normal concrete. All the walls and accompanying small
specimens such as cylinders and prisms were conditioned in a specially-constructed high
temperature and high humidity chamber to accelerate the reaction and deterioration. This
paper will present results from these walls that were tested in three phases under lateral
displacementexcursionswhilesimultaneouslysubjectedtoaxialloadthussimulatingseismic
loads.Inthefirstphase,afterabout6monthsofconditioning,theASRwallwasfoundtohave
about14%highercapacitythannormalwallalthoughtheASRconcretestrengthandstiffness
valuesweremuchlowerthanthoseofnormalconcrete.Inthefinalphaseaftertheexhaustion
ofASRreaction,theASRshearwallshowedsignificantlylessductilebehaviourcomparedto
the normal wall and similar ASR walls tested in low damage phase. Ductility and ultimate
lateraldisplacementofthewallswereconsiderablyreducedasASRexpansionprogressed.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0117- Modeling corrosion of reinforcement in concrete: accelerated vs. Natural
corrosion
JoškoOžbolta,b,GojkoBalabanićb
aUniversityofStuttgart,InstituteofConstructionMaterials,Pfaffenwaldring4,Stuttgart,
Germany,[email protected]
bUniversityofRijeka,FacultyofCivilEngineering,RadmileMatejčić3,Rijeka,Croatia,
Chloride-inducedcorrosionofsteelreinforcementinconcreteisoneofthemajorcausesfor
deteriorationofreinforcedconcretestructures.Therefore,topredictdurabilityofRCstructure
itisimportanttohaveanumericaltool,whichisabletopredictcorrosionprocessesandtheir
consequences for the structural safety. The main problem in formulating such models is
quantifying controlling parameters for processes before and after depassivation of
reinforcement.
Thefirstobjectiveofthepresentcontributionistovalidatetherecentlydeveloped3Dchemo-
hygro-thermo-mechanicalmodelforconcretebymeansofanextensiveexperimentalprogram,
whichincludestestsundernaturalandlaboratorycontrolledconditions.Particularattention
is paid in characterizing the parameters of the hysteretic moisture model as well as the
concreteconductivity.
Theexperimentsrelatedtothecorrosionofsteelreinforcementinconcreteareusuallycarried
out under accelerated conditions. The results of such experiments are then used in the
formulationofdesignformulas.However,therecanbealargedifferencebetweenaccelerated
andnaturalcorrosion.Forinstance,thecorrosionproductsaresignificantlydifferent,i.e.the
expansionfactorofcorrosionproductsincaseofacceleratedcorrosionismuchsmallerthan
inthecaseofnaturalcorrosion.Moreover,distributionofcorrosionoverthereinforcement
surface for the same geometry can be different. To illustrated these differences numerical
studyforthebeam-endspecimenwithstirrupsisperformedforbothcases.Thespecimenis
firstexposedtoacceleratedandnaturalcorrosion.Subsequently,themainreinforcementbar
is pulled-out out from the specimen to investigate the influence of the corrosion induced
damageonthepull-outcapacity.Toverifythemodel,theresultsofacceleratedcorrosionare
alsocomparedwiththeavailableexperimentalresults.Itisclearlydemonstratedthatthere
aresignificantdifferencesbetweentheresultsobtainedforacceleratedandnaturalcorrosion.
Especially the position and variation of corrosion rate over the main reinforcement and
stirrupsareratherdifferent.Therefore,theexperimentalresultsobtainedunderaccelerated
corrosionconditionsshouldbeusedinthepracticewithspecialattention.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0287-Agedependentshearresistanceofreinforcedandprestressedconcrete
LinWan-Wendnera,RomanWan-Wendnerb
aPostdoctoralResearchFellow,PolitecnicodiMilano,[email protected]
bDirector,ChristianDopplerLaboratory,BOKU,Vienna,[email protected]
Conventionalfiniteelementsoftwareandassociatednumericalmodelsaretypicallyusedto
analyzethemechanicalbehaviorofstructuralscaleconcretebeams.However,theylackthe
ability toaccount for theheterogeneityofconcreteoraginganddeteriorationeffects.This
paper introduces a comprehensive computational framework to model the behavior of
reinforcedandprestressedconcretebeamsundershear load.The frameworkconsists ofa
discrete particle model incorporating effects from concrete aging, creep, shrinkage and
prestressloss.Five-meterlongconcretebeamswithfullreinforcementanddifferentprestress
levelsweretestedundershearloads.Materialtestsoftheconcreteonvariousages,including
unconfinedcompression,uniaxialteststomeasuremodulusofelasticity,splittingtests,and
fracture tests were carried out. Concrete creep and shrinkage measurements were also
conductedtostudytheireffectonprestresslossandconsequentlytheshearresponse.The
modelconstructsthebeamwithconcreteasdiscreteparticlesandthesteelrebars/tendons
as beam elements. The concrete behavior is defined by constitutive laws with its material
propertiescalibratedbasedonstandardexperimentaltests.Thebehaviorofreinforcedrebars
and prestressing tendons follow the elasto-plastic law of typical steel with known Young’s
modulusandyieldingstrength.Therebarbeamelementsandsolidconcreteelementsinteract
with each other using penalty constraints. Before the shear load is applied, creep and
shrinkagelossesofconcreteareevaluated,ofwhichtheparameterswerecalibratedbasedon
the experimental measurements. The results of the predictive shear simulations for the
reinforcedandprestressedbeamsresemblethoseofthetestedspecimensincludingbutnot
limitedtotheforce-displacementresponses,thefailuretypes,andthecrackpatterns.Withthe
well-calibrated and validated aging framework, the shear resistance of the prestressed
concretememberscanbeaccuratelypredicted.
Engineering Mechanics Institute
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A0593-Probabilisticmodeloftheyieldingstrengthforthecorrodedrebars
X.Gaoa,Y.Panb
aAssociateProf.,TongjiUniversity,[email protected]
bMasterstudent,TongjiUniversity,[email protected]
Corrosionoftherebar isthemajortriggerofthecrackofthecover, thedegradationofthe
bondperformanceandthebearingcapacityoftherebar.Therefore,thebearingcapacitywill
bedecreasedandeventhefailuremodeoftheRCmembersmaychangefromtheductilefailure
to the brittle failure. The degradation of the bearing capacity and the time-dependent
reliabilityofreinforcedconcretememberscanbepredictedaccuratelyonlyifthevarietyof
theyieldingstrengthofthecorrodedrebarhasbeenacquired.Inthispaper,1706testdata
collectedfrom31referenceswereclassifiedintothreegroupsaccordingtothecauseofthe
corrosionwhichwereconstantcurrentacceleratedcorrosion(CCAC),acceleratedcorrosion
test in simulated environment(ACTSE) and in-suit corrosion of the practical RC
members(ISCA).Basedontheexistingresearch,theyieldingstrengthoftheunstainablepart
of the corroded rebar is the same as the normal rebar. Accordingly, the minimum cross-
sectionalareaofthecorrodedrebaratthedifferentcorrosionrateisthekeyissuetoobtain
thebearingcapacityofthecorrodedrebar.
ByusingLillieforstest,theabnormaldataweredeleted.Theprobabilitydistributionmodelof
the minimum normalized section area k of corroded steel bars of the three cases follows
normaldistribution.Accordingtotheanalyzedresults,itisfoundthatthechangeofthemean
valueofkISCAisminimalwiththeincreaseofthecorrosionrate,whilethemeanvalueofkACTSE
decreasedthemost.Thereby,whenCCACandACTSEmethodsareadopted tosimulate the
corrosionoftherebar,thenormalizedminimumsectionareakshouldberevisedbythefactors
presentedinthepaper.Meanwhile,thedistributionofthemeanvalueofkISCAismorescattered
whenthecorrosionrateincrease.Thepresentedprobabilisticmodeloftheyieldingstrength
forthecorrodedbarswasverifiedbyusingtheconfidenceintervalof50%and95%.Whenthe
confidenceintervalis50percent,morethanhalfofthedatawasintheconfidenceinterval.
Almostallofthedataisintheconfidenceintervalwhentheconfidenceintervalis95percent.
ItisprovedthattheprobabilitydistributionmodelofkISCAproposedinthispaperisaccurate
andreliable,andhasgoodapplicability.Moreover,thebearingcapacityofaRCbeamswere
calculatedduetothedifferentcorrosionrateofthe longitudinalbarsandthestirrups.It is
proved that the failure mode of the RC beams can change from the flexural failure to the
shearingfailure.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0708-AtheoreticalframeworkforcreepeffectanalysisofaxialloadedshortCFST
columnsunderhighstresslevels
ShiweiLia,YongqingYangb
aDr.,SouthwestJiaotongUniversity,[email protected]
bProf.,SouthwestJiaotongUniversity,[email protected]
Duetoitsexcellentmechanicalperformances,axialloadedconcrete-filledsteelcirculartube
(CFST)columnshavebeenwidelyusedinstructuralengineering.Asanimportantlong-term
behaviorofCFSTstructures,creephasanobviousnonlinearpropertyunderhighthestress
levels,i.e.,creepisnotlinearlydependentonthestresses,whichmakestheinfluenceofcreep
more complicated. In this study, to analyze the impacts of nonlinear creep effect on the
behaviorofaxial loadedshortcfstcolumns,acompletetheoretical frameworkforcoupling
analysis of 3D creep effect and material nonlinearity was presented. First, to simulate the
plasticity and damage evolution of concrete core under high stress levels, a new concrete
plasticitydamagemodelwithuniformconstraint(UCCDP)wasestablished.Next,basedonthe
UCCDPandcreepPossionratio,a3Dnonlinearcreepanalysismethodandthecorresponding
numerical analysis method were established, which was implemented into the ABAQUS
secondaryplatform.Finally,bycomparingthepredictedresultswithexperimentalresultsin
different stress levels, this approach for predicting the creep of axial loaded short CFST
columnshasexhibitedsatisfactoryaccuracy.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS3: Instabilities and Bifurcations in Solids, Structures
and Soft Materials
A0026-Actuatingsoftmaterialsinsurgeryrobotapplications
BoLia,DichenLib,ShuxinWangc,HualingChend,GuiminChene
aAssociateProfessor,Xi’anJiaotongUniversity,[email protected]
bProfessor,Xi’anJiaotongUniversity,[email protected]
cProfessor,TinjinUniversity,[email protected]
dProfessor,Xi’anJiaotongUniversity,[email protected]
eProfessor,Xi’anJiaotongUniversity,[email protected]
Conventional surgical robot are in straight-bar shape and made of rigid materials mostly,
which fail to adapt to the minimally invasive surgical operation using natural orifices.
Therefore,wedevelopaflexiblesurgicalrobotbasedonsoftmaterials.Multi-DOFdeformation
andvariablestiffnessabilitiesviaelectro-pneumaticactuationandfiberjammingtechniques,
ispresented.Theintegratedmanufacturingprocessofthemanipulatorunitisdeveloped.An
experimentaltestsystemissetuptoobtainthenonlinearrelationshipsbetweenthebending
deformation,outputforceofthepneumaticartificialmuscleactuatorandtheairpressure,by
eliminatingtheinstability.Therelationshipsbetweenanti-bendingabilityofasingleunitand
negative pressure, fiber arrangement and fiber density are further studied. The optimized
designschemeisobtained.Withinacomplexsystem,themulti-DOFdeformationinbypass,
thetrackingandthestiffnesstunabilityofthemanipulatoraredemonstrated.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0054-Patterntransitionsinasoftcylindricalshell
FanXua,YifanYangb,Hui-HuiDaic,MichelPotier-Ferryd
aInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronanutics,FudanUniversity,Shanghai,P.R.China,[email protected]
bInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronanutics,FudanUniversity,Shanghai,P.R.China,[email protected]
cDepartmentofMathematics,CityUniversityofHongKong,HongKong,P.R.China,
dUniversitédeLorraine,CNRS,ArtsetMétiersParisTech,LEM3,F-57000Metz,France,
Instabilitypatternsofrollingupasleeveappearmoreintricatethantheonesofwalkingover
a rug on floor, both characterized as systems of uniaxially compressed soft film on stiff
substrate.Thiscanbeexplainedbycurvatureeffects.Toinvestigatepatterntransitionsona
curvedsurface,westudyasoftshellslidingonarigidcylinderbyexperiments,computations
and theoretical analyses. We reveal a novel postbuckling phenomenon involving multiple
successivebifurcations:smooth-wrinkle-ridge-saggingtransitions.Theshellinitiallybuckles
intoperiodicaxisymmetricwrinklesatthethresholdandthenawrinkle-to-ridgetransition
occursuponfurtheraxialcompression.Whentheloadincreasestothethirdbifurcation,the
amplitudeoftheridgereachesitslimitandthesymmetryisbrokenwiththeridgesagginginto
a recumbent fold. It is identified that hysteresis loops and the Maxwell equal-energy
conditions are associated with the coexistence of wrinkle-ridge or ridge-sagging patterns.
Such a bifurcation scenario is inherently general and independent of material constitutive
models.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0061-Amodelingandresolutionframeworkforwrinklinginhyperelasticsheets
atfinitestrain
C.FUa,T.Wangb,F.Xuc,Y.Huod,M.Potier-Ferrye
aInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected],
bInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected],
cInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected],
dInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected],
eUniversitédeLorraine,CNRS,ArtsetMétiersParisTech,LEM3,F-57000Metz,France,
Wrinklesarecommonlyobservedinuniaxiallystretchedrectangularhyperelasticmembranes
with clamped-clamped boundaries, and can disappear upon excess stretching. Here we
developamodelingandresolutionframeworktosolvethiscomplexinstabilityproblemwith
highlygeometricandmaterialnonlinearity.Themainadvantagesofthisframeworkinclude
thegeneralityforbothcompressibleandincompressiblematerials,easeofprogramming,high
precision and efficient continuation predictor. Moreover, various compressible or
incompressiblemodelscanbesystematicallyderivedbasedon3Dstrainenergypotentials,
e.g.,Saint-VenantKirchhoff,neo-Hookean,Mooney-Rivlin,GentmodelandGent-Gentmodel.
Basedontheproposedapproach,effectofdifferentincompressibleconstitutivemodelsonthe
post-buckling response is quantitatively investigated, which shows limited influence on
bifurcationdiagrams.However,forcompressiblematerials,Poisson’sratioplaysacriticalrole
inthewrinklingandrestabilizationbehavior.WefindthatsmallerPoisson’sratiomakeslater
onsetofwrinkling, loweramplitudeandearlierdisappearanceofwrinkles.Besides,severe
strain-stiffeningphenomenaareexploredbyaccountingforphenomenologicalmodelssuch
asGentmodelandGent-Gentmodel.Efficiencyandaccuracyofthemethodwereexaminedby
comparingwithexperimental,numericalandanalyticalbenchmarks.
Engineering Mechanics Institute
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A0069-Onthewrinkingandrestabilizationofhighlystretchedrectangularsheets
T.Wanga,C.Fub,F.Xuc,Y.Huod,M.Potier-Ferrye
aInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai,P.R.China,[email protected],
bInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai,P.R.China,[email protected],
cInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai,P.R.China,[email protected],
dInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai,P.R.China,[email protected],
eUniversitédeLorraine,CNRS,ArtsetMétiersParisTech,LEM3,F-57000Metz,France,
Wrinkles are commonly observed in uniaxially stretched rectangular sheets with clamped-
clampedboundaries,andcandisappearuponexcessstrtching.Hereweexplorethiswrinkling
andrestabilizationbehaviorbothanalyticallyandnumerically.Effectofdifferentconstitutive
models, i.e., Saint-Venant Kirchhoff, neo-Hookean and Mooney-Rivlin, on the post-buckling
responseareinvestigated,whichshowsratherlimitedquantitativeinfluenceonbifurcation
diagrams. Poisson’s ratio, however, plays a crucial role in the wrinkling and restabilization
behavior.WefindthatsmallerPoisson’sratiomakeslateronsetofwrinkling,loweramplitude
andearlierdisappearanceofwrinkles.Inparticular,whenPoisson’sratioisbelowathreshold,
nowrinklesoccur,whichcanbeexplainedbythedecreasingtransversecompressivestresses
withrespecttothereducingPoisson’sratio.Futhermore,basedontheKoiterbucklingtheory,
wehavesemi-analyticallypredictedsecondarybifurcationpointsforthefirsttime,through
looking into the sign change of the quadratic terms in potential energy. Both theoretical
bucklingandsecondarybifurcationpointsareingoodagreementwithfiniteelementresults.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
61
A0089-Morphable3Dmesostructuresandmicroelectronicdevicesbymultistable
bucklingmechanics
YihuiZhanga
aDepartmentofEngineeringMechanics,TsinghuaUniversity,Beijing,P.R.China
Three-dimensional(3D)structurescapableofreversibletransformationsintheirgeometrical
layouts have important applications across a broad range of areas. Most morphable 3D
systems rely on concepts inspired by origami/kirigami or techniques of 3D printing with
responsivematerials,sometimesreferredtoas4Dprinting.Thedevelopmentofschemesthat
can simultaneously apply across a wide range of size scales and with classes of advanced
materialsfoundinstate-of-the-artmicrosystemtechnologiesremainsagrandchallenge.This
talkintroducesasetofconceptsformorphable3Dmesostructuresindiversematerials(e.g.,
device-grade silicon, metals and polymers) and fully formed planar devices, including
integratedelectronicsystemswithhighperformancecapabilities,spanninglengthscalesfrom
micrometers to millimeters. The approaches rely on elastomer platforms deformed in
differenttimesequencestoelasticallyalter,withengineeringcontrol, the3Dgeometriesof
supported mesostructures via controlled processes of non-linear mechanical buckling.
Comprehensivestudiesofmulti-stabilityandcorrespondingenergylandscapesinthiscontext
establish general design strategies. Demonstrations include experimental and theoretical
investigationsofover20examples,includingmesostructuresthatcanbereshapedbetween
differentgeneralizedandrecognizablegeometriesaswellasthosethatcanmorphintothree
ormoredistinctstates.Twofunctionallyreconfigurablemicroelectronicdevices,includingan
adaptiveradiofrequencycircuitandaconcealableelectromagneticdevice,provideexamples
oftheseconcepts.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0121-Wrinklingofsoftbiomaterials
BoLia
aAssociateProfessor,TsinghuaUniversity,[email protected]
Biological materials often exhibit diverse morphologies, which can arise from either
physiologicalorpathologicalgrowth.Inthisstudy,wecombinetheoreticalanalysis,numerical
simulations,andexperimentalobservationtoelucidatehowthesemorphologiesaredriven
anddictated.Takingbiofilmsandmucosaeas twotypicalexamples,weshowthatresidual
stressesresultingfromdifferentialgrowthofbiologicalmaterialsareabletotriggersurface
wrinkling,whichleadstovariouspatterns.Phasediagramsareestablishedtodemonstratethe
rolesofthickness,elasticmoduli,andinterfacebondinginregulatingthesewrinklingpatterns.
Itisfoundthatgeometricalcurvatureandinterfacialdelaminationcanfurtherenrichsurface
wrinkling.Ourstudyhighlightstheroleofmechanicsinsculptingbiologicalmorphogenesis.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
63
A0154- Morphological evolution of buckle-delamination: from telephone cord
blistertobeyond
ShichenLia,LongMab,SenjiangYuc,YongNid
aCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,DepartmentofModern
Mechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China,
bCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,Departmentof
ModernMechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China,
cInnovativeCenterforAdvancedMaterials(ICAM),HangzhouDianziUniversity,Hangzhou,
P.R.China,[email protected]
dCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,Departmentof
ModernMechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China,
Understandingandcontrollingspontaneouscomplexnature’spatternformationisofbroad
interestinbothscientificandengineeringcommunities.Highresidualcompressivestressin
thin film-substrate systems usually causes structural and functional failures via buckling
instability. In particular, they could buckle and delaminate away from the substrate, and
exhibit complex buckle-delamination patterns, such as straight-sided, circular, ring-like,
telephonecordornetwork-likeblisters.Inthistalk,wefocusonelucidatingsomeuniversal
morphological features of such telephone cord blisters and beyond via a combination of
theoreticalanalysis,numericalsimulationandexperimentalvalidation.Howinterfacesliding
andridgecrackingonvariousbucklinginstabilitymodesandhowtheseinstabilitiesevolve
intocomplexbuckle-delaminationpatternsobservedinourexperimentsarediscussed.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0174- Modeling and simulation of the electro-mechanical coupling behavior of
liquidcrystalelastomers
YiweiXua,YangZhangb,YiqingZhangc,YongzhongHuod
aInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected]
bInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected]
cInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected]
dInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,220HandanRoad,Shanghai,P.R.China,[email protected]
Liquid crystal elastomers (LCEs) are weakly cross-linked polymers with liquid crystal
mesogenic units and can exhibit liquid crystallinity. They are a type of soft active/smart
materialsthatcanhavelargespontaneousdeformationsinresponsetoexternalstimulusand
providesomefunctionsthatweneed.LCEscouldbepolarizedunderelectricfields,andthe
directorofLCunitscanrotatethendrivethepolymernetworktodeform.So,LCEsexhibits
interesting electro-mechanical coupling behavior. Other attributes of them include fast
responseandlowcost.ThedeformationandelectricpolarizabilityofLCEsarecouplewith
eachother.
Basedonthevariationalprinciple,wehavederivedtherelevantconstitutiveandgoverning
equationsincludingtheequationsfortheelectricfieldinducedLCdirectorreorientation.We
use this model to analyze and simulated deformations of LCE samples under electric-
mechanical loading. The results indicated that when the initial alignment is uniform, the
sampleofLCEstripeexhibituniformdeformationunderelectricfields.Notethatthereisa
criticalelectricfieldintensityatwhichtheinitiallyperpendicularlyorientedLCdirectorwill
bringinstabilityandstarttoreorient.WecallittheFreedericksztransitioninLCE.Iftheinitial
alignment is nonuniform, the stripe can bend. In both cases, the behavior of deformations
depend strongly on the initial alignment. Therefore the behavior of LCE samples could be
regulatedthroughproperdesignoftheinitialalignment.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0195-Interactionsbetweentopologicaldefectnucleationandboundarybranching
inthegrowthofcurvedcrystals
LongMaa,XuepengLiub,Ai-kahSohc,LinghuiHed,YongNie
aCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,DepartmentofModern
Mechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China
bCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,Departmentof
ModernMechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China
cSchoolofEngineering,MonashUniversityMalaysia,SubangJaya,Malaysia
dCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,Departmentof
ModernMechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China
eCASKeyLaboratoryofMechanicalBehaviorandDesignofMaterials,DepartmentofModern
Mechanics,UniversityofScienceandTechnologyofChina,Hefei,Anhui,P.R.China
Topologicaldefectnucleationandboundarybranchingincrystalgrowthoncurvedsurfaceare
twotypicalelasticinstabilitiesdrivenbycurvatureinducedstress,andseparatelydiscussed
inthepast.Inthisworktheyaresimultaneouslyconsideredduringcrystalgrowthonasphere.
Phasediagramswithrespecttocurvatureofthesphere,size,edgeenergyandstiffnessofthe
crystal for the equilibrium crystal morphologies are achieved by theoretical analysis and
validatedbyBrowniandynamicssimulations.Thesimulationresultsfurtherdemonstratethe
detailofmorphologicalevolutionbythetransitionandinterplaybetweenthesetwodifferent
stress relaxation modes. Topological defect nucleation and boundary branching not only
competeeachotherandbutalsocoexistinarangeofcombinationsofthefactors.Clarification
of the interaction mechanism provides better understanding of various curved crystal
morphologiesfortheirpotentialapplications.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0216-Curvatureeffectonwrinklingandrestabilizationofhighlystretchedelastic
shells
Y.Yanga,T.Wangb,K.Wangc,F.Xud
aInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai200433,P.R.China,[email protected]
bInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai200433,P.R.China,[email protected]
cSchoolofTraffic&TransportationEngineering,CentralSouthUniversity,Changsha410075,
P.R.China,[email protected]
dInstituteofMechanicsandComputationalEngineering,DepartmentofAeronauticsand
Astronautics,FudanUniversity,Shanghai200433,P.R.China,[email protected]
Rectangularsheetswithclamped-clampedboundariescanwrinkleuponuniaxialstretching
andthenreverttoflatstateuponexcessloading.Onemaywonderwhatwouldhappenona
curvedshell?Toinvestigatethecurvatureeffect,weexploreanopencylindricalshellunder
axialstretching,bothexperimentallyandnumerically.Ourresultsindicatethatthecurvature
playsan importantrole in thewrinklingandrestabilizationbehavior.Curvaturemakesthe
peakandvalleyofwrinklesnotsymmetric,which showsaglobal-localcoupling instability
phenomenon.Besides,comparedwithplanargeometry,curvaturedelaystheappearanceof
wrinkles,whileitmakesthesecondarybifurcationofrestabilizationmuchearlier.Thereexists
acriticalmaximumvalueofthecurvaturetobuckletheshell.Beyondthisvalue,nowrinkles
occur during axial stretching. Hyperelastic constitutive models (e.g., neo-Hookean and
Mooney-Rivlin laws)andsiliconrubbermembranesareusedinnumericalsimulationsand
experiments,respectively.Theresultscanpromiseanoveldirectiontocontrolthewrinkling
instabilityofmembranes.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
67
A0250-Mechanicsofnanofiberspackinginvesicles:effectsoffiberlength,radius,
andelasticity
XinYia
aDepartmentofMechanicsandEngineeringScience,CollegeofEngineering,Peking
University,[email protected]
Cellular packing of one-dimensional nanomaterials, including natural cytoskeletal
microtubules,actinfilaments,syntheticnanotubesandnanowires,isoffundamentalinterest
to the understanding of a wide range of cell activities, including cell shape control, cell
movement,celldivision,andnano-cytotoxicity.Tounderstandtheunderlyingmechanicsof
cellular/intracellular packing, we perform theoretical analyses and molecular dynamics
simulationstoinvestigatehowthemorphologyandmechanicalbehaviorsofalipidvesicleare
regulatedbyencapsulatednanofibersofdifferentlengths,finiteradii,andelasticity.Astherod
lengthincreases,thevesicleevolvesfromasphereintodifferentshapes,suchasalemon,a
congadrum,acherry,abowlingpin,oratubularshapeforlong,thick,andstiffnanofibers.
Moreover,weestablishapackingphasediagrambasedonthreedistinctvesiclemorphologies,
includinga non-axisymmetricdumpling-shapedvesicle withastronglycurvednanofiber,a
cherry-shapedvesiclewithatubularmembraneprotrusionenclosingasignificantportionof
the nanofiber, and an axisymmetric lemon-shaped vesicle with a pair of protruding tips
inducedbytheencapsulatednanofiber.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0298-Astatespacemethodforonsetofsurfaceinstabilityofgradedsoftmaterials
ZhigenWua,ChunxiaoZhanb
aSchoolofCivilEngineering,HefeiUniversityofTechnology,Hefei,Anhui,China,
bSchoolofCivilEngineering,HefeiUniversityofTechnology,Hefei,Anhui,China,
Surfaceinstabilitywidelyexistsinnatureandhasbeenexploitedforarangeofapplications.
Inthisstudy,basedonthegoverningequationsandbydiscretizingthematerialproperties
intopiecewiseconstantfunctions,astatespacemethodisdevelopedtosolvetheeigenvalue
problemandpredictthecriticalconditionforonsetofsurfaceinstabilityofgradedhydrogel
layers and graded elastic cylinders. For the hydrogel system, the state space solutions for
homogeneoushydrogellayers,hydrogelbilayers,andcontinuouslygradedhydrogellayersare
presented.Forgradedelasticcylinders,thestatespacesolutionsforathincylindricalshell,a
bilayeronasoftcylinder,andexponentiallygradedelasticcylindersareobtained.Thepresent
solutions are compared with the analytical solutions and/or finite element results. In
particular,atransitionofthecriticalbucklingmodeforasoftcylindercoveredbyabilayeris
illustratedclearlybythepresentmethod.Incontrasttothefiniteelementmethod,thestate
spacemethodisasemi-analyticalapproachwithgoodconvenienceandhighercomputational
efficiencyforarbitrarilygradedmaterials.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
69
A0318-Theamplitude-frequencyresponseofthincompositeplateinthethermal
environment
LiuLiua,JinmingLib
aSchoolofAerospaceEngineering,BeijingInstituteofTechnology,Beijing,PRChina
bSchoolofAerospaceEngineering,BeijingInstituteofTechnology,Beijing,PRChina
This paper deals with the dynamic response of a thin composite plate under a harmonic
excitationinathermalenvironmentusingincrementalharmonicbalancemethod(IHB).The
nonlineargoverningequationsofthemotionisdevelopedbasedontheKirchhoffhypothesis
andvon-Karmangeometricnon-linearity.Galerkin'smethodisutilizedtoderivethenonlinear
governing equation of the problem with cubic nonlinearities associated with mid-plane
stretching.Anincrementalarc-lengthmethodcombinedwithacubicextrapolationtechnique
isadoptedtotracetheamplitude-frequencyresponsecurve.Theperiodicsolutionsandthe
stabilityare investigatedusingtheIHBmethod.Thesolutionofamplitude-frequencycurve
has been validated by the comparison of the results obtained by the IHB method and the
numerical method. Variation of amplitude-frequency response curve and dynamic
equilibrium position of thin plate with different temperature rising and same external
excitation are presented. The results demonstrate that the combination of thermal
deformationandthetemperaturerisinggovernsthedynamicresponse.Asthetemperature
increases, the transition of a hardening-spring type nonlinear dynamic response to a
softening-typeinthepost-criticalregionduetotwostableequilibriaforthethincomposite
plateinthethermalenvironmenthasbeenpresented.Furthermore,thedynamicbehavioris
becomingcomplicatedastheexternalexcitationfrequencyisclosetothenaturalfrequencyof
plate,whichcontainsthetypicalresonance,super-harmonic,sub-harmonicresonanceandthe
combinationofthem.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0342-Photo-responsivesurfacewrinklingpatterns
JuanjuanWanga,ChuanyongZongb,HaipengJic,EnpingLiud,LeleLie,YanpingCaof,
FanXug,AndreasFeryh,ConghuaLui
aSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
bSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
cSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
dSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
eSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
fDepartmentofEngineeringMechanics,TsinghuaUniversity,Beijing,China
gDepartmentofMechanicsandEngineeringScience,FudanUniversity,Shanghai,China
hLeibnizInstituteofPolymerResearchDresdene.V.,D-01069Dresden,Germany
iSchoolofMaterialsScienceandEngineering,TianjinUniversity,Tianjin,China
Recentlystimuli-responsivesurfacemicrostructureshaveattractedincreasinginterestowing
to their wide applications. Here we report the dynamic modulation of surface instability-
driven surface patterns on photo-sensitive film/substrate systems by introducing azo-
containingfunctionalgroups.Theinfluencesofthesubstrate,theincidentlightintensity,and
light polarization on surface wrinkling behavior have been investigated. Different
photoresponsivepropertiesoftheazo-containingfilmareexploitedtoaccumulate/releasethe
bilayer compressive stress, and induce the reversible switching between surface wrinkling
and dewrinkling states, which has been supported by the theoretical results. We take
advantageofthecharacteristicsofourlight-responsivecompositesystemfortheapplication
of all-optical reversible writing/erasure of (confidential) information, smart windows, and
welloptically-regulatedgratings,as demonstratedhere.This light control strategycoupled
with surface wrinkling is expected to furnish the use of azopolymers in the area of smart
surfacefabricationwhichcanfinddiversenovelapplicationsinsmartdisplay,optoelectronic
devices,andsensors,etc.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0397-Aconsistentfinite-strainplatetheoryforgrowth-induceddeformationsand
instabilitiesofsoftmaterialsamples
J.Wanga,D.Steigmannb,F.F.Wangc,H.-H.Daid
aSchoolofCivilEngineeringandTransportation,SouthChinaUniversityofTechnology,
Guangzhou,Guangdong,China,[email protected]
bDepartmentofMechanicalEngineering,UniversityofCalifornia,Berkeley,CA,USA,
cDepartmentofMathematics,EastChinaUniversityofScienceandTechnology,Shanghai,
China,[email protected]
dDepartmentofMathematics,CityUniversityofHongKong,83TatCheeAvenue,Kowloon
Tong,HongKong,[email protected]
Growthofsoftbiologicaltissueswiththinplateforms(e.g.,leaves,petals,wingsofinsectsand
skin)canbecommonlyobservedinnature,duringwhichthesofttissuesusuallyundergolarge
deformationsandexhibitvariousmorphological instabilities.Toproperlystudythegrowth
deformationsofsofttissuesorotherkindsofsoftmaterialsamples,asuitableplatemodelis
desired. In the present work, a novel finite-strain plate theory for growth-induced large
deformations is developed. This plate theory was established within the framework of
nonlinearelasticity,takingintoaccountthegrowtheffectsandtheelasticincompressibility.
Derivation of the plate theory contains the following steps: 1) formulate the 3D governing
system of the plate sample through variational approach, which includes the mechanical
equilibrium equation and the constraint equation of incompressibility; 2) expand the
unknownfunctionsintermsofthethicknessvariable,andestablishtherecursionrelationsof
the expansion coefficients from the mechanical equilibrium equation and the constraint
equation; 3) derive the 2D vector plate equation from the lower and the upper boundary
conditionsinthe3Dgoverningsystem;4)proposetheassociatededgeboundaryconditions
fortheplateequationandderivetheweakformulationforfuturenumericalcalculations.It
canbeverifiedthat theplateequationsystemisconsistentwith theoriginal3Dgoverning
systemtoO(h2).Toshowthevalidityoftheplatetheory,twoexamplesregardingthegrowth-
induceddeformationsandinstabilitiesinthinhyperelasticplatesarestudied.Someanalytical
results are obtained in these two examples, which can be used to describe the large
deformationsandrevealtheinstabilitypropertiesofthethinplates.Furthermore,theresults
obtainedfromthecurrentplatetheoryarecomparedwiththoseobtainedfromtheclassical
FvKplatetheory,fromwhichtheadvantagesofthecurrentplatetheorycanbedemonstrated.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0426-Edgewrinklingofasoftridgewithgradientthickness
YanZhaoa,YanpingCaob
aAssociateProfessor,HunanUniversity,[email protected]
bProfessor,TsinghuaUniversity,[email protected]
We investigate the edge wrinkling of a soft ridge with gradient thickness under axial
compression.Ourexperimentsshowthatthewrinklingwavelengthundergoesaconsiderable
increase with increasing load. Simple scaling laws are derived based on an upper-bound
analysistopredictthecriticalbucklingconditionsandtheevolutionofwrinklingwavelength
duringthepost-bucklingstage,andtheresultsshowgoodaccordancewithourfiniteelement
simulationsandexperiments.Wealsoreportapatterntransformationtriggeredbytheedge
wrinkling of soft ridge arrays. The results and method not only help understand the
correlationbetweenthegrowthandformobservedinsomenaturalsystemsbutalsoinspire
astrategytofabricateadvancedfunctionalsurfaces.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0433-Controllablerollingandconfigurablebendinginflexiblenanomembranes
ZiaoTiana,YongfengMeib
aDepartmentofMaterialsScience,StateKeyLaboratoryofASICandSystems,Fudan
University,Shanghai,PRChina
aDepartmentofMaterialsScience,StateKeyLaboratoryofASICandSystems,Fudan
University,Shanghai,PRChina,[email protected]
Rolled-up nanomembranes can take advantage of strain-engineering and form into three
dimensional(3D)tubularstructuresforvariousapplicationsincludinglab-on-a-chip,micro-
/nanomachines, optical microcavity, sensors and actuators. Extensive attention has been
focusedontheirstrainengineering,controlandprocessrelatedtobendingbehaviors.Here
wewillintroducethemethodandprocessofrolled-upnanotech.Withspecifiedmaterialsand
processadopted,history-dependentrollingandconfigurablebendingwillbedemonstrated
for diamond helical structures and stimuli-responsive actuators. We believe that
nanomembraneorigami(e.g.rolling,bendingandstretching)couldofferanexcitingplatform
for3Dmesostructuresandtheirapplications.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0483-Localizedbulginginaninflatedbilayertube
YangLiua,YangYeb
aDepartmentofMechanics,TianjinUniversity,Tianjin,China,[email protected]
bDepartmentofMechanics,TianjinUniversity,Tianjin,China,[email protected]
Gent model is believed to be an excellent model for rubber material, where an important
parameterJmsignifiesthemaximumextensibility.ItturnsoutthatarubbertubemadeofGent
materialcannotbulgeforsmallJm.Inthistalk,weconsiderabilayertubeconsistingofGent
materials. By virtue of a bifurcation condition derived for a single-layer tube of arbitrary
thickness,westudythelocalizedbulgingofthebilayertube.Ourresultsuggestsapossible
waytopreventlocalizedbulgingbybondingalayerofspecifiedthicknesswhichcannotbulge
inside or outside. Furthermore, the theoretical prediction is validated by finite element
analysis.Accordingly,theapplicabilityofthebifurcationconditionisalsoconfirmed.Onthe
otherhand,bothvolumecontrolandpressurecontrolproblemsarediscussed,andtheeffects
ofthemodulusratioandthicknessratioonthecriticalpressurePcr triggeringabulgingor
criticalvolumeVcrareinvestigated.Forthepressurecontrolproblem,wefindthatalargerPcr
attainsifthestiffpartofthebilayerincreasesoronelayerbecomesstiffer.However,thecase
ofvolumecontrolisdifferent.ItisfoundthatVcrisanon-monotonefunctionofthepercentage
ofthestiffpart.Alltheoreticalresultsarevalidatedbythecorrespondingnumericalonesusing
ABAQUS.Finally,westudythegrowthandpropagationofthelocalizedbulgingemployingthe
finiteelementmethod.Itturnsoutthattheeffectsofgeometricalandmaterialparameterson
the maximum axial stretch and propagation pressure are similar to those on the critical
pressureandvolume.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0484-Wrinklingofdielectricelastomermembranes
Yu-XinXIEa,ZhendeHOUb,YibinFUc
aSchoolofMechanicalEngineering,TianjinUniversity,[email protected]
bSchoolofMechanicalEngineering,TianjinUniversity,[email protected]
cDepartmentofMathematics,KeeleUniversity,[email protected]
Apre-stretchedsheet,beingpartlycoveredwithelectrodesonbothofitssides,andtheratio
oftheelectricactivatingareaissetas ,willwrinkleunderanelectricactivation.Inthiswork,
acomputationalmodeltocharacterizethewrinklingisproposed.Basedonthismodel,some
critical values, such as the critical voltage, applied stretch, et al. can be determined. The
relationbetweenthecriticalvaluesandthenumberofwrinklesarealsoanalyzed.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0493-Patternformationincurvedfilm-substratesystems
M.Potier-Ferrya,C.Fub,T.Wangc,F.Xud,R.Abdelmoulae
aLEM3,UniversitédeLorraine,Metz,France,[email protected]
bDepartmentofAeronauticsandAstronautics,FudanUniversity,Shanghai,China,
cDepartmentofAeronauticsandAstronautics,FudanUniversity,Shanghai,China,
dDepartmentofAeronauticsandAstronautics,FudanUniversity,Shanghai,China,
eLSPM,UniversitéParis-Nord,Villetaneuse,France,[email protected]
Stress-inducedpatternformationandpatternselectionofthinfilm/substratesystemshave
motivatedalotofresearchesduringthelastfifteenyears.Mostoftherecentpapersfocuson
planarfilm/substratebilayersandonlyfewareconcernedwithcurvedgeometry.Inthistalk,
westudythecurvatureeffectonthebucklingandpost-bucklingofsuchstructures,especially
cylindricalandsphericalsystems,fromtheoreticaltonumericalpointsofview.Thebehavior
ofsuchstructuresassociatingastifffilmandasoftcoreisinvestigatedbyusinga3Dfinite
elementmodel,thefilmbeingdiscretizedbythinshellelements.Asforpureshellstructures
(i.e.withoutacore),theinstabilityschemeisloadingandgeometry-dependent.Inthecaseof
anaxiallycompressedcylindricalpureshell,thebucklingmodesareknowntobediamond-
like and the buckling response is subcritical and highly imperfection-sensitive. The same
scheme holds with a soft core, but the response becomes supercritical and the mode
axisymmetricwithastiffercore.Itisestablishedthattheinfluenceofthecoreisgovernedby
dimensionlessparameters,Cs=(R/hf)3/2Es/EfinaxialcompressionandCth=(R/hf)3/4(L/hf)3/2
ES/Efinthecaseofathermalshrinkageofthesubstrate.Inthecaseofasphericalsystemunder
pressure, the mode keeps the same hexagonal shape as without substrate, but the post-
bucklingbehaviortendsalsotobecomesupercriticalforastiffcore.Roughlythemodeshapes
remainoftenthesamewithandwithoutsubstrate,butthepost-bucklingresponsebecomes
generally stable with a stiff substrate, what was almost never observed with pure shell
structures.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0650- Non-sinusoidal buckling patterns turned by micro-structure of
film/substratesystem
ShuyiXianga,b,ChangguoWanga,b
aNationalKeyLaboratoryofScienceandTechnologyonAdvancedCompositesinSpecial
Environments,HarbinInstituteofTechnology,HarbinP.R.China
bCenterforCompositeMaterialsandStructures,HarbinInstituteofTechnology,HarbinP.R.
China
Thegeometryofthemicro-structureonthesoftsubstrate,whichisrecognizedbyanarrayof
micro-columns, can significantly influence buckling patterns and buckling load of stiff
film/soft substrate system. When the column is relatively thin, non-sinusoidal buckling
patterns will appear. With finite element eigenvalue analysis, the column is found to
participateinbendingortensiledeformation.Theresultcanbeexplainedqualitativelybythe
change of energy distribution between film and substrate with micro-structure, which is
different from the traditional film/substrate system with perfect interface. Whatever the
geometry of micro-structure is, there will exist quasi-sinusoidal buckling pattern, which is
calledupward-buckling.Inthepastresearch,thebucklingofnon-contactfilmissimplifiedas
theEulerbucklingoftheends-clampedbeams.Itisfoundthatthissimplificationonlyapplies
tothesituationwhenthecolumnisquitethin.Asthewidthofthecolumnincreases,itwill
causesignificanterrors.Therefore,wemodelthefilmasabeamelasticallyrestrainedagainst
rotation whose extreme case is ends-clamped beam or ends-fixed beam. With the help of
numeralcalculations,theelasticrotationalstiffnessappliedtothebeamcanbeobtained.The
elasticrotationalstiffnesscanbeusedasameasureoftheconstrainteffectofcolumnonthe
non-contactfilm,whichiscloselyrelatedtothegeometryofmicro-patternsandcanguidethe
predictionofbucklingload.
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A0715-Electromechanicalcatastrophe
TongqingLuaa
aAssociateProfessor,StateKeyLabforStrengthandVibrationofMechanicalStructures,
DepartmentofEngineeringMechanics,Xi’anJiaotongUniversity,
A transducer is a system that couples two loads. For a membrane of dielectric elastomer
sandwichedbetweentwocompliantelectrodes,itcouplesamechanicalforceandanelectrical
voltage.Attributesofadielectricelastomertransducerincludelargedeformation,highenergy
density, lowcostandfastresponse.Applicationsincludeactuators,generatorsandsensors.
Such a two-load, nonlinear system can exhibit rich behavior of bifurcation, which can be
displayedinathree-dimensionalspace,withthetwoloadsformingthehorizontalplaneand
a state variable forming the vertical axis. In this three-dimensional space, a state of
equilibriumofthesystemunderfixedloadscorrespondstoapointonthesurface,calledthe
behaviorsurface.Thesurfaceissmooth,butthesingularitytheoryprovesthattheprojection
ofthebehaviorsurfacestotheloadplaneresultsinsingularityoftwotypes:foldandcusp.
Hereweidentifythefoldandcuspforadielectricelastomertransducerbyacombinationof
theory and experiment. We construct a three-dimensional space, with one axis being the
stretch,andtheothertwoaxesbeingtheelectricalandmechanicalloads,andthenweproject
thesurfaceontothevoltage-stretchplane,force-stretchplaneandtheforce-voltageplane.We
conducttwokindsofexperiments:electricalactuationunderaconstantforceandmechanical
pullingunderaconstantvoltage.Goodagreementbetweenthetheoryandtheexperimentis
obtainedbothonthedeformationhistoryandthedeterminationoffoldsandcusp.Thefold
andcuspareessentialinthedesignofloadingpathstoavoidorharnessthebifurcation.
Engineering Mechanics Institute
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79
A0844-Analysisandpredictionofunevensettlementduetoacurvedshieldmetro
tunnel
Surface settlement is a natural phenomenon of ground disturbance in subway tunnel
construction. Dissymmetrical surface settlement profiles are observed when shielding in a
curved tunnel, but these observations are quite different from the predictions of typical
formulaewhichindicateasymmetricalsurfacesettlementprofileinstraighttunnels.
Based on the field measurements from shielding subway tunnels in soft ground located in
SoutheastAsia,therelationoftheunevendistributionofjackingthrustandthemechanicsof
dissymmetricalsettlementarediscussed,andthemethodofcalculatingthedissymmetrical
settlementprofileisproposedinthisstudy.Themethodsproposedinthisarticlecanbeused
to properly predict the surface settlement induced by a single curved tunnel in similar
geological and construction conditions. The results also provide a reference set of shield
constructionparameters.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS4: Computer Vision-based Studies in Structural
Health Monitoring
A0372-Systemidentificationandseismicresponsemonitoringoflarge-scalebridge
modelsusingtarget-trackingdigitalimagecorrelation
LunaNgeljaratana,MohamedA.Moustafab
aGraduateStudentResearcher,DepartmentofcivilandEnvironmentalEngineering,
UniversityofNevada,Reno
bAssistantProfessor,DepartmentofcivilandEnvironmentalEngineering,Universityof
Nevada,Reno,[email protected]
The objective of this presentation is to demonstrate the potential use of video monitoring
techniques for bridge system identification, structural health monitoring, and seismic
responseevaluationforpost-earthquakeoperationand/orrepairdecisionmaking.Thepaper
presents the results and discussion of target-tracking and digital image correlation (DIC)
monitoring of two large-scale (about 1/3 scale) two-span bridges under bidirectional
earthquakeloadingintheEarthquakeEngineeringLaboratoryofUniversityofNevada,Reno.
This study consists of two parts. The first part aims at validating and verifying response
monitoring from DIC using data from conventional sensors, i.e. string displacement
potentiometers and triaxial accelerometers. This part of the study also presents the
comprehensive monitoring and comparison of the overall seismic response of the bridge
systemsanddynamicinteractionatdifferentlevelsofseismicexcitation.Thesecondpartof
this study focuses on the structural system identification of both bridges with the
determinationofstructuralmodelparametersbasedonDICmeasuredresponsedata.Before
andaftereachseismictest,lowamplitudewhitenoisebaseexcitationtestswereconducted
and in turn, a quasi-linear response of the system was assumed to estimate the modal
parametersofanequivalentlineartime-invariant(LTI)modelforeachbridgesystem.Using
thestructuralvibrationdatarecordedbyDICandaccelerometers,threesystemidentification
methods,includingsingle-output-singleinput(SISO),singleinput-multipleoutput(SIMO)and
two output-only (SSI-DATA) are used to estimate the modal identification, i.e. frequency,
damping,andmodeshapesofthebridges.
Engineering Mechanics Institute
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A0387- Automatic bolt loose detection based on digital image processing
technology
LinshengHuoa,YuLiub
aAssociateProfessor,SchoolofCivilEngineering,DalianUniversityofTechnology,
bMaster’sStudent,SchoolofCivilEngineering,DalianUniversityofTechnology,
Boltconnectionisanimportantconnectionforminbridges,buildings,pipelines,transmission
towers,andothercivilstructures.Theloosenessoftheconnectionnodeinstructuresoften
leadstothedamageorevencollapseofstructuralsystems,hencethemonitorandinspection
ofboltsconnectioninstructuresareveryimportant.Ingeneral,looseboltscouldbevisually
inspected by inspectors to assess health status. However, traditional visual inspections are
time-consuming,cumbersomeandinaccurate.Withthedevelopmentandmaturityofimage
processingtechnology,imageprocessingcouldbeappliedtolooseboltdetectionoflarge-scale
structures, which is an automatic and rapid detected method to ensure the safety during
detection process This paper proposes a method of automatic bolt looseness detection, all
testing processes are automatically completed in one step, including preprocessing, edge
recognition,imagecorrectionandanglecalculation.Inthisstudy,weidentifiedtherotation
angleofthenutfromtheimages,bythefollowingsteps:First,cameracaptureboltphotos.and
then, the images were corrected by image processing techniques and bolt edges were
extracted.Finally,determiningtheangleofeachboltandcalculatingtherotationangle.We
verified the applicability of this method through a set of experiments. The results
demonstrated that the measurement error of this method was less than 5.5%, which
suggestedthatthismethodcouldaccuratelydetecttheloosenessofbolts.
Engineering Mechanics Institute
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A0910- An algorithm for identification of structural parameters and excitation
forcesusingnoncontactvision-baseddisplacementmeasurements
YingLeia,XianzhiLib,JubinLuc
aDepartmentofCivilEngineering,XiamenUniversity,XiamenChina
bDepartmentofCivilEngineering,XiamenUniversity,XiamenChina
cDepartmentofCivilEngineering,XiamenUniversity,XiamenChina
The identification of structural parameters and external excitation forces is important for
structuralhealthmonitoring(SHM).Duringthepasttwodecades,althoughrecentresearches
have demonstrated some maturity for vibration-based SHM, the requirement for installing
densepoint-wisesensor(e.g.,accelerometers,straingauges,LVDT,etc.)networkswouldtake
considerable measurement cost, time and effort, and traffic disruptions. Due to the recent
advancesinsensortechnologyandcomputationalcapabilityofcomputers,theuseofvision-
based approaches for condition assessment of structures offer a promising alternative
opportunitytoimprovetheresilienceofstructuralsystems.Incontrasttotheconventional
extensively used point-wise sensors, displacements of a large number of points can be
extractedbycomputervision.Onemajoressentialtaskistofurtheradvancethenoncontact
vision sensor technology for practical SHM applications, by validating the feasibility of the
simultaneousidentificationofstructuralstiffnessandexternalexcitationforcesutilizinglow-
costvision-baseddisplacementdata.Inthispaper,therecentgeneralizedextendedKalman
filter,which recentlyhasbeenproposedbytheauthors, isextendedtoinvestigatethereal
time simultaneous identification of both structural stiffness and external excitation forces
utilizingvision-baseddisplacementmeasurementidentificationofstructuralparametersand
excitationforcesusingdisplacementmeasurements.Anumericalexampleisinvestigatedto
evaluate the accuracy of the proposed algorithm. Effects of different noise levels, sensor
numbersandinitialestimatesofstructuralparametersontheidentifiedresultsarestudiedin
detail.Theproposedalgorithmcanbeintegratedwithcomputertechnologyforefficientand
low-cost periodic or long-term performance assessment of civil infrastructures for the
resilienceofstructuralsystems.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS5: Nonlinear Stochastic Structural Dynamics
Methodologies for Complex Engineering Systems
A0659-Anefficientstochasticcomplexmodalanalysistechniquefornonclassically
dampedandnonlinearmdofstructuralsystems
IoannisP.Mitseasa,IoannisA.Kougioumtzogloub,MichaelBeerc
aInstituteforRiskandReliability,LeibnizUniversityHannover,Callinstr.34,30167,
Hannover,Germany,[email protected],[email protected]
bDepartmentofCivilEngineeringandEngineeringMechanics,TheFuFoundationSchoolof
EngineeringandAppliedSciences,ColumbiaUniversity,500West120thStreet,NewYork,
NY10027,USA.e-mail:[email protected]
cInstituteforRiskandReliability,LeibnizUniversityHannover,Callinstr.34,30167,
Hannover,Germany
Anovelinelasticmodaldecompositionmethodforrandomvibrationanalysisinallingnment
withcontemporaryaseismiccodeprovisions(e.g.,EC8)consideringnon-classicallydamped
andnonlinearmulti-degree-of-freedom(MDOF)systemsisdeveloped.Relyingonstatistical
linearization and state-variable formulation the complex eigenvalue problem considering
non-classicallydamped,nonlinearMDOFstructuralsystemssubjecttoavectorofstochastic
seismic processes characterized by power spectra compatible in a stochastic sense with a
givenelasticresponseuniformhazardspectrum(UHS)ofspecifiedmodaldampingratio,will
beaddressed.Equivalentmodalproperties(EMPs)of the linearizedMDOFsystem,namely
equivalentpseudo-undampednaturalfrequenciesandequivalentmodaldampingratioswill
be provided. To this aim, the system response covariance matrix needs to be estimated.
Subsequently,theEMPsofthestructurewillbeutilizedtogetherwiththeappropriatemean
response elastic UHS for determining peak nonlinear responses. Note that a significant
advantageofthetechniquerelatestotheinvolveddecouplingandthederivedEMPswhichare
notonlyabletocapturethetrendoftheinelasticbehavior,buttheyarealsoclearlyamenable
toaphysicalmeaning.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0802-Ahybridsem‒smmethodforsubwayrandomdynamicloadsinducedbythe
frequency-dependentdynamicpropertiesofrailpads
KaiWeia,b,YinlingDoua,b,FanYanga,b,ShaohuaWanga,b,PingWanga,b
aMOEKeyLaboratoryofHigh-speedRailwayEngineering,SouthwestJiaotongUniversity,
Chengdu,China
bSchoolofCivilEngineering,SouthwestJiaotongUniversity,Chengdu,China
Foraneffectiveandaccuratepredictionofthemainexcitationsourceofsubwayenvironment
vibrationsandwheel‒railnoise(i.e.,therandomdynamicloadsofsubwayvehicles),according
totheperiodicityofrail‒fastenersystemandhigh-frequencyelasticwavecharacteristicsof
rail, a hybrid SEM‒SM method is proposed. Based on the measurement of the frequency-
dependentdynamicpropertiesofDTIIIrailpadsfrequentlyusedinChina’ssubway,thehybrid
SEM‒SMmethodwasusedtoinvestigatetheinfluenceofthefrequency-dependentdynamic
properties of DT III rail pads on subway random dynamic loads. There are four main
conclusions.(1)ThestoragestiffnessofDTIIIrailpadwithin0.1–10000Hzat20°Chavean
approximatelinearrelationwithfrequencyinalogarithmiccoordinatesystem,whiletheloss
factors of DT III rail pad firstly increase and then decrease in frequency domain. (2) The
frequency-dependent dynamic properties of rail pads can increase the subway random
dynamicloadsintwodominantfrequencydomains,32‒80Hzand500‒1250Hzrespectively.
Thus, the frequency-dependent dynamic properties of rail pads should be considered in
predictionofsubwayenvironmentalvibrationandwheel–railnoise.(3)Theinfluenceofthe
frequency-dependentdynamicpropertiesofrailpadsonsubwayrandomloadsisequivalent
totheeffectofthevehiclespeedincreaseof92km/h,whiletheinfluenceoftheshortwave
trackirregularityonsubwayenvironmentvibrationsislessthantheeffectofthefrequency-
dependentdynamicpropertiesofrailpadsunlessthereisaprettyseriousshortwavetrack
irregularity.(4)TheproposedhybridSEM‒SMmethodinwhichonlyoneelementisrequired
tocomputethehigh-ordervibrationmodesofinfiniterailisappropriateforhigh-efficiency
analysisofsubwayrandomdynamicloadsinhighfrequencies.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0890- Stochastic response analysis of an offshore wind turbine under the
excitationsrepresentedbystochasticharmonicfunction
YupengSonga,JianbingChenb
aPh.D.student,CollegeofCivilEngineering,TongjiUniversity,[email protected]
bProfessor,StateKeyLaboratoryofDisasterReductioninCivilEngineering,
Simulationofthewindandwaveloadsactingonanoffshorewindturbineisoneofthemost
criticaltasksinitsstructuraldesignandreliabilityassessment.Thespectralrepresentation
method(SRM)isthemostwidelyusedmethodatpresent,which,however,involvesalarge
numberofrandomvariablesandresultsinmuchcumbersomenessinthereliabilityanalysis
of the system. To reduce the random variables in the simulation of fluctuating wind speed
fields,thestochasticharmonicfunction(SHF)representationwasdevelopedrecentlybased
onawavenumber-frequencyjointspectrum.ComparedtotheSRM,intheSHFrepresentation
method both the phase angles and frequencies/wavenumbers are regarded as random
variables. Along this line, the wave surface elevation is also simulated through the SHF
representation in the present paper. Besides, the subdomains involved in the SHF
representation are specified by the Voronoi cell partitioning scheme after determining the
representative points by the acceptance-rejection method. In this way, the number of the
randomvariablesandthecomputationaleffortsaredramaticallyreducedsimultaneously.For
illustrativepurpose,thestochasticdynamicresponseanalysisofanoffshorewindturbineis
addressed,demonstratingtheeffectivenessoftheproposedmethod.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS6: Damage Modelling of Engineering Structures
A0169- Concurrent fatigue crack growth and vehicle-bridge dynamics analysis
usingtime-basedsybcycleformulation
YangYua,YongmingLiub,KarthikRajanVenkatesanc,BiancaKuriand
aPostdoctoralFellow,SchoolforEngineeringofMatter,Transport&Energy,ArizonaState
University,[email protected]
bProfessor,SchoolforEngineeringofMatter,Transport&Energy,ArizonaStateUniversity,
cPh.D.student,SchoolforEngineeringofMatter,Transport&Energy,ArizonaState
University,[email protected]
dMasterstudent,SchoolforEngineeringofMatter,Transport&Energy,ArizonaState
University,[email protected]
Bridgestructuresareproneto fatiguedamagesas theyundergotraffic loading.Thebridge
responses under vehicle loading are usually complex due to the interaction between the
vehicleandbridge.Theclassicalcycle-basedformulationforfatiguecrackgrowthhasintrinsic
difficulties in dealing with these complex loading spectrums since they often cannot be
describedascyclic.Inthisstudy,atime-basedsubcycleformulationforfatiguecrackgrowth
isintroducedtoaddressthisdifficulty.Theproposedmodelincludesthreemajorcomponents:
1)atime-basedcrackgrowthkineticsfunctionatthesubcyclescale;2)anefficientcracktip
opening displacement (CTOD) estimation method; 3) a crack tip plasticity zone tracking
algorithms for crack opening level determination of a moving crack. For demonstration, a
simplysupportedsteelgirderbridgeisadopted.Numericalsimulationisconductedusingfull-
scalethree-dimensionalvehicleandbridgemodels.Aninitialcrackisassumedtobelocated
onthebottomflangeofthesteelgirderandthecrackgrowthisanalyzedusingtheproposed
method.Aparametricstudyisconductedtoinvestigatetheeffectsofroadsurfacecondition,
vehicleweight,vehiclespeed,vehicledynamics,andtrafficvolumeonthecrackgrowthrate.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0406-Datanormalizationanddamagedetectionframeworkforoperationalwind
turbinesinvaryingoperationalenvironments
OmidBahramia,JeromeLynchb
aGraduateStudent,DepartmentofCivilandEnvironmentalEngineering,Univ.ofMichigan
bProfessor,DepartmentofCivilandEnvironmentalEngineering,Univ.ofMichigan
Wind turbines are complex engineered structured designed to convert wind energy into
electricalenergy.Theirlargesizecoupledwithanextremelydemandingloadenvironmentcan
leadtodamageoverthelife-spanofthewindturbine.Giventheirhighcostsandimportance
in providing electrical energy, there is growing interest in monitoring wind turbines and
assessing their health using monitoring data. A major challenge associated with structural
healthmonitoring(SHM)ofwindturbinesisthevaryingnatureoftheirenvironmentaland
operationalconditions(EOC).ThisworkexploresanapproachtoextractingEOCdatafrom
the measured structural response of wind turbines. A data normalization process is
performedbyclusteringEOCfeaturesmeasuredusingaGaussianmixturemodel.With the
EOCspacedelineatedbyclustering,datafromanoperationalturbineinanunknownstateis
assigned by EOC features to a cluster. Damage-sensitive features also extracted from
monitoringdataisthencomparedtothebaselinehealthystateofthestructureforagivenEOC
clustertohypothesizetheconditionofthestructure.Thisframeworkisvalidatedusingasmall
5 kW wind turbine located in Los Alamos, New Mexico. A wireless monitoring system is
installedontheturbinetomeasurethelateralvibrationoftheturbinetower.Theacceleration
datacollectedisusedtoassesstheconditionofthestructure.Acontrolleddamagestateis
introducedintheformofasoftspringintroducedattheturbinefoundation.Thestudyfinds
themethodspresentedareeffectiveinclassifyingthehealthofthestructure.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0451- Simulating time-dependent quasi-brittle failures based on a multilinear
releasingmechanismofviscousforcefields
JinxingLiua
aFacultyofCivilEngineeringandMechanics,JiangsuUniversity,XuefuRoad301,Zhenjiang,
Jiangsu,China,
The time-dependent progressive failure processes in heterogeneous brittle materials are
modeledbyconsideringthetemporalstressredistributionmechanismduetolocalbreakages.
The influence of local breakages lies in two successive kinds of stress redistributions: (1)
Internalforcesinthebreakingelementisassumedtoreleaseinfinitelyfastwhencompared
with external loadings, while the specimen takes time to deform correspondingly due to
materialviscosity.Thisdeformationdelayisimplementedbyintroducingaviscousforce(VF)
fieldalloverthespecimen.(2)ThesecondisthegradualreleaseofVFfieldsstoredpreviously
which is approximated as a multilinear process. The algorithm only includes linear
computations and is free of nonlinear iterations. Numerical results of uniaxial
tensile/compressive,anchorboltpull-outandBraziliantestsshowthattheproposedmodelis
capableofovercomingtheover-brittleissueinexistinglatticemodelsandcapturingthestrain
ratesensitivity,whichagreewellwithexperimentalobservations.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0477-Machinelearningbasedmultiscalemodelingofbackwarderosionpiping
AlessandroFascettia,CaglarOskayb
aLecturer,FacultyofScienceandEngineering,TheUniversityofWaikato(Hamilton,New
Zealand),[email protected]
bProfessor,DepartmentofCivilandEnvironmentalEngineering,VanderbiltUniversity
(Nashville,TN,USA),[email protected]
The presented research provides a novel multiscale modeling framework to simulate the
evolutionofBackwardErosionPiping(BEP)processesinFloodProtectionSystems(FPSs).
Numericalsimulationsareperformedatthelocalscalebymeansofamultiphasedescription,
andresultsareusedasthetrainingsetforamulti-layerMachineLearning(ML)algorithmto
bridge the information between scales. The capability of generating results in a fast, yet
accurate manner is exploited in the parametric study of the proposed physical model.
AccuracyofthesotrainedMLalgorithmisdemonstratedbycomparingresultsobtainedfrom
detailednumericalmodels.Themultiscaleapproachisalsoemployedintheconstructionof
responsetables,whichpresentresultsinaconvenientgraphicalfashion.Thegoalofthisstudy
istoallowforreal-timepredictionsoftheoverallresponseatthesystemscalelevel.Acase
studyispresentedwheretheentireportionoftheNashvilleMetroLeveeSystemisstudiedin
aspanofayear,toassessthelikelihoodofBEPtoundermineitsstability.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0651-Analysisofseismiccollapseofhigh-risestructureundernear-faultpulse-
typegroundmotion
TiancanHuanga,MinLib
aEarthquakeEngineeringResearch&TestCenterofGuangzhouUniversity,
bEarthquakeEngineeringResearch&TestCenterofGuangzhouUniversity,
Thenear-faultpulse-typegroundmotionshasgreatpotentialdamageabilitytothehigh-rise
structure, which will increase the risk of seismic collapse of structures. In this study,
incremental dynamic analysis method combined with material damage model was used to
quantitatively analyze the seismic collapse of a high-rise building subjected to near-fault
pulse-typegroundmotions.Inparticular,thepaperfocusesontheanalysisoftherelationship
betweentheP-delteeffectandtherelatedenergychanges,which.arecloselyrelatedtothe
structuralcollapse.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
91
A0827- Scaling effects for dynamic responses with application to buried arches
subjectedtointernalblast
SzeDaiPanga
aAssociateProfessor,NationalUniversityofSingapore,[email protected]
Earth covered arch structures provide an economical solution for storing ammunition and
otherexplosivematerials.Toassesstheblastresistanceofthestoragestructure,experimental
study is always necessary, because any analytical or numerical models require verification
basedonexperimentalresults.Ascomparedtofull-scaleexperiments,scaleddownmodeltest
isamuchcheaperandeasieralternative.So far,mostof thescaledmodelexperimentsare
conductedusingreplicascalingmethod,inwhichthemodelsaregeometricallyscaledfrom
the prototype while keeping the material properties unchanged. However, three common
phenomena,namelystrainrateeffect,concretefractureandgravity,violatethereplicascaling
law,andhencetheymaypotentiallydiminishtheaccuracyofthescalingresults.
Thisresearchiscarriedouttofirstevaluatetheeffectofeachnon-scalingphenomenoninthe
blastloadedburiedarches,andthen,forthemoreprominentsourcesofscalingdistortions,to
proposenewscalingmethodstoreducethescalingerrors.Numericalsimulationsshowthat
thestrainrateeffectandconcretefracturearethetwomajorscalingdistortions,whereasthe
scaling errors due to gravity effect is insignificant. Therefore, new scaling methods are
requiredtoreducethescalingerrorsduetostrainrateeffectandconcretefracture.
Anewsetofscalinglaw,thestrainratescaling,isdevelopedtoreducethescalingerrorsdue
tothestrainrateeffectinsteelmaterial.Numericalsimulationsareperformedonblastloaded
buriedsteelarchestoprovethesuperiorscalingperformanceofthestrainratescalingover
the classical replica scaling. The strain rate scaling method is also applicable to other
dynamically loaded steel structures, and the wide applicability of the new scaling law is
demonstratedthroughnumericalsimulations.Aseriesofmodelandprototypedrop-weight
impactexperimentsareperformedtoillustratetheapplicationprocessandtofurthervalidate
thestrainratescalinglaw.Thestrainratescalinglawisalsoextendedtosituationswherethe
modelandtheprototypearebuiltfromdifferentsteelgrades.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0879- Constitutive modeling of ductile and brittle failures of semicrystalline
polymers
Jia-LiangLea,AnuTripathib,SusanMantellc
aDepartmentofCivil,Environmental,andGeo-Engineering,UniversityofMinnesota
bDepartmentofCivil,Environmental,andGeo-Engineering,UniversityofMinnesota
cDepartmentofMechanicalEngineering,UniversityofMinnesota
Semicrystalline polymers, such as high density polyethylene (HDPE), have become
increasinglypopularininfrastructureapplicationsduetotheirlowcostandhighstrength-to-
weightratio.However,manyoftheseengineeringapplicationsinvolvecorrosiveenvironments,
which cause material embrittlement and eventually catastrophic structural failures. This
studyaimstodevelopaconstitutivemodeltocapturethetransitionbetweentheductileand
brittlefailuresofHDPEbasedonthemolecularweightandcrystallinity.Anelaso-viscoplastic
model is used to capture the ductile behavior due to the intermolecular resistance of the
crystalline and amorphous phases, as well as the entangled network resistance of the
amorphousphase.Thecontributionsfromtheindividualphasestotheoverallloadresistance
is governed by the polymer crystallinity. These plastic deformation mechanisms lead to
networkdisentanglement,crystalbreakdown,andinitiationofmicro-voids.Thevoidgrowth
inthecrystallineandtheamorphousphasecausestheductilefailureofthepolymer.Whenthe
maximumprincipalstressintheamorphousphasereachesacriticalvalue,micro-voidswould
localizeintocrazes,andthegrowthandbreakdownofthesecrazescausecrackpropagation
signifying a brittle failure mode. To capture this transition of the failure mechanism, a
continuum model of crazing damage is combined with the elasto-viscoplastic model. The
model parameters are explicitly related to the molecular weight of the HDPE, and its
dependence is calibrated by using the uniaxial tensile tests at various deformation rates,
crystallinities,andcorrosionlevels.Theconstitutivemodelisvalidatedbythefiniteelement
simulationsofdoubleedgenotchtestsfordifferentcorrosionlevels.Itisshownthatthemodel
can capture well the time-dependent stress-strain behavior and predict the transition
betweentheductileandbrittlefailuremodesofHDPEinacorrosiveenvironment.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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MS7: Non-Deterministic Modelling and Uncertainty
Management in Structural Dynamics and Vibroacoustics
A0044- Structural reliability and reliability sensitivity analysis of extremely rare
failureeventsbycombiningsamplingandsurrogatemodelmethods
PengfeiWeia,JingwenSongb
aAssociateProfessor,SchoolofMechanics,CivilEngineeringandArchitecture,Northwestern
PolytechnicalUniversity,[email protected]
bPh.Dstudent,SchoolofAeronautics,NorthwesternPolytechnicalUniversity,
Theaimofthispaperistostudythereliabilityanalysis,theparametricreliabilitysensitivity
(PRS)analysisandtheglobalreliabilitysensitivity(GRS)analysisofstructureswithextremely
rare failureevents.Firstly, theGRS indicesarerestudied,andweshowthat the totaleffect
indexcanalsobeinterpretedastheeffectofrandomlycopyingeachindividualinputvariable
on the failure surface. Secondly, a new method, denoted as AK-MCMC, is developed for
adaptivelyapproximatingthefailuresurfacewiththeactivelearningKrigingsurrogatemodel
aswellasthedynamicallyupdatedMonteCarlo(MC)orMarkovChainMonteCarlo(MCMC)
populations.Thirdly,theAK-MCMCprocedurecombinedwiththequasi-optimalimportance
sampling(IS)procedureisextendedforestimatingthefailureprobability,thePRSandGRS
indices. For estimating the GRS indices, two new IS estimators are derived. The AK-MCMC
procedurecanberegardedasacombinationoftheclassicalAK-MCSandsubsetsimulation
(SS)procedures,butitismuchmoreeffectivewhenappliedtoextremelyrarefailureevents.
Resultsoftestexamplesshowthattheproposedmethodcanaccuratelyandrobustlyestimate
theextremelysmallfailureprobability(e.g.,1e-9)aswellastherelatedPRSandGRSindices
withseveraldozensoffunctioncalls.
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International Conference 2018 November 2-4 Tongji University
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A0079- Model-form and parameter uncertainty quantification in structural
vibrationsimulationusingfractionalderivatives
BaoqiangZhanga,c,QintaoGuob,YanWangc,MingZhand
aSchoolofAerospaceEngineering,XiamenUniversity,[email protected]
bCollegeofMechanicalandElectricalEngineering,NanjingUniversityofAeronauticsand
Astronautics,[email protected]
cWoodruffSchoolofMechanicalEngineering,GeorgiaInstituteofTechnology,
dCollegeofMechanicalandElectricalEngineering,NanjingUniversityofAeronauticsand
Astronautics
Extensiveresearchhasbeendevotedtoengineeringanalysisinthepresenceofonlyparameter
uncertainty.However,inmodelingprocess,model-formuncertaintyarisesinevitablydueto
thelackofinformationandknowledge,aswellasassumptionsandsimplificationsmadeinthe
models. It isundoubtedthatmodel-formuncertaintycannotbe ignored.Tobetterquantify
model-formuncertaintyinvibrationsystemswithmultipledegreesoffreedom,inthispaper,
fractional derivatives as model-form hyperparameters are introduced. Two types of
hyperparameters for damping and elasticity force are differentiated. A new general model
calibration approach is proposed to separate and reduce model-form and parameter
uncertaintybasedonmultiplefractionalfrequencyresponsefunctions.Thenewcalibration
method is verified through a simulated system with two degrees of freedom. The studies
demonstratethatthenewmodel-formandparameteruncertaintyquantificationmethodis
robust.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0129- Dynamic response of a train-bridge intraction system due to sudden
decelerationinhighspeedrailwaysystems
XuzhaoLUa,Chul-WooKIMb,Kai-ChunCHANGc
aPh.Dcandidate,DepartmentofCivilandEarthResourcesEngineering,KyotoUniversity,
bProfessor,DepartmentofCivilandEarthResourcesEngineering,KyotoUniversity,
cJr.AssociateProfessor,DepartmentofCivilandEarthResourcesEngineering,Kyoto
University,[email protected]
Thisstudyisintendedtoinvestigatedynamicresponsesofatrain-bridgeinteractionsystem
withasuddendecelerationutilizingthecommercial finiteelementsoftwareABAQUSasan
emergencybrakeoftrainisacrucialtechnicalissueinhighspeedrailwaysystem.Fewstudies
have investigated dynamic responses of train-bridge interaction system with a series of
decelerationtraincars.Therefore,thisstudyalsoexaminestheinfluenceofemergencybrake
ofaseriesoftraincarsonthebridgestrucure.AtypicalShinkansensystem—Japanesehigh-
speedrailway,whichconsistsof16carsanda3-blockbridgeisthetargetrailwaysystemto
beinvestigated.Thecarcomprisescarbodies,bogiesandwheelsets,whichareallmodelled
byrigidbodiesandconnectedwithspringsanddampers.Thebridgeismodeledwithsolid
elements.Asfortheinteraction,apenaltyfrictionmethodisappliedtosimulatetheextreme
locking brake case when sliding happens between wheels and tracks. This model was
compared with a general deceleration model. The emergency brake showed considerable
effectsonlongitudinalaccelerationoftrainvehiclesandverticaldynamicresponsesonpre-
specifiedpointsofthebridge.Itisnoteworthythatobservationsfromthisstudycanprovide
referenceinformationofimpactfactorsandridingcomfortoftrainfordesigncodes.Moreover,
the proposed numerical approach encourages to extend the application to investigation of
trainandbridgeresponsesinextremesituationssuchasderailment.
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A0145- A robust approach to quantifying forecasting uncertainty using proxy
simulations
KendraVanBurena,ScottCoganb,FrançoisHemezc
aTechnicalStaffMember,XComputationalPhysicsDivision(XCP),LosAlamosNational
Laboratory,LosAlamos,[email protected]
bResearchFellow,UniversiteBourgogneFranche-Comte,Besançon,France.
cTechnicalStaffMember,XTheoreticalDesign(XTD)Division,LosAlamosNational
Laboratory,LosAlamos,[email protected]
When using numerical models, analysts are often confronted with the situation whereby
simulationpredictionsareusedtoinformdecision-makinginadomainwhereexperimental
dataareunavailable.Insuchcases,thenumericalmodelistrustedtopredictintheapplication
domainsimplybecauseithasbeenshowntobetrustworthyinthevalidationdomain,where
experimentaldataareavailable.Thedifferencebetweenapplicationandvalidationdomains,
however,canoftenresultinsignificantextrapolationofthemodelthatreducesconfidencein
predictions in the application domain, for example, when a model validated against linear
vibrationdataisusedtopredictin-serviceperformancewhenanonlinearresponseisinduced.
Thechallengeofpredictingintheapplicationdomainisfurtherexacerbatedduetothefact
thatcalibrationcanresultinparameteruncertaintyinducedby(i)modelformerror,whichis
the inability of the numerical model to exactly replicate physics, and (ii) lack of model
distinguishability,whichoccurswhendifferentsetsofparametervaluesareabletoreplicate
theexperiments.Forthesereasons,calibrationresultsinparametervaluesthatreflectabest
fit to experimental data rather than converging to their "true" values. Thus, calibration
introduces compensating effects to parameter values that must be accounted for when
predictingineitherthevalidationorapplicationdomains.
Although the inherent dangers of prediction extrapolation are widely recognized, few
methods are available to actually establish its credibility for a given application. It is our
contention that numerical predictions should be as robust as possible to sources of
uncertaintywhenpredictingintheapplicationdomain.Herein,weproposeanapproachto
calibrationthatutilizes info-gapdecisiontheorytoprovideameasureofrobustnesstothe
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combined effects of extrapolation and compensating errors. Rather than searching for
parametervaluesthatbest-fitexperimentaldatainthevalidationdomain,ourmethodology
is to search for parameter values that are robust in both the validation and application
domains.Satisfyingboundaries,whichareisocontoursoftheparametervaluesthatproduce
fidelity-equivalentsolutionsintheparameterspace,canbecomparedinboththecalibration
domainandtheapplicationdomaintoformulatearobustnessindicator.Doingsocaninform
thedegreetowhichcalibrationerrorscanbetoleratedwhilestillensuringacriticallevelof
forecastingrobustness.Thebasicpremiseisthatrobustnesstotheeffectsofcompensating
errorsandextrapolationcanbequantifiedusingpredictionvariabilitywhenparametervalues
are allowed to vary away from their calibrated settings. Robust calibration is performed
considering the ability to replicate experimental data in the validation domain, and proxy
simulationsrepresentativeoftheapplicationdomain.Ourmethodologyisdemonstratedusing
asimplifiedstructure.Ourapproachhighlightsthefactthat,confidenceinmodelpredictions
intheapplicationdomainisincreasedwhenpredictionsremainasrobustaspossiblegiven
theunavoidablesourcesofuncertaintyinthenumericalmodel.
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A0323-Modelingtheasymmetricdependantsoilvariables
YiZhanga
aAssociateProfessor,DepartmentofCivilEngineering,TsinghuaUniversity,
Multivariate information of soil parameters is quite important for the design and risk
assessment of geotechnical engineering problems. It is necessary to have an accurate and
realisticstatisticalmultivariatemodelforrepresentingthesoilpropertiesandthusevaluating
the soil conditions. Thus, advanced multivariate modeling of soil parameters could help to
improve the geotechnical engineering practice. In this paper, the asymmetric copulas are
introducedtomodelthegeotechnicalsoildata.Comparedtoextensivepreviousresearchon
theuseofsymmetriccopulasonthemodelingofengineeringdata,thisstudyisfocusingon
capturingasymmetricdependenciesamongthenaturalsoilparameters,whicharecriticalto
engineeringdesigns.Acopula-basedmultivariateprobabilisticmodelisbuiltbasedonasetof
collected samples from a granite residual soil from Portugal. Several asymmetric copula
functions,capableofcapturingnonlinearasymmetricdependencestructures,aretestedand
analyzed. The fundamental information on tail dependencies and measures of asymmetric
dependenciesarealsoexploited.Todemonstratetheadvantagesofasymmetriccopulas,the
asymmetriccopulaconceptiscomparedwiththetraditionalcopulaapproachesformodeling
sitesoildata.Theperformanceoftheseasymmetriccopulasisdiscussedandcomparedbased
ondatafittingandextremevaluecharacterizations.
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A0414- Non-probabilistic model of transmissibility functions based on complex
ratiointervalarithmetic
Meng-YunZhaoa,Wang-JiYanb,Wei-XinRenc
aDepartmentofCivilEngineering,HefeiUniversityofTechnology,[email protected]
bDepartmentofCivilEngineering,HefeiUniversityofTechnology,[email protected]
dDepartmentofCivilEngineering,HefeiUniversityofTechnology,[email protected]
Due to its clear physical interpretation in characterizing the dynamics of a system,
transmissibility functions play important roles in many related fields such as structural
damage detection and modal analysis. Uncertainty quantification for transmissibility
functions is of practical importance in improving the robustness of their real applications.
Interval analysis has been a popular mathematical tool to deal with the uncertainties of
engineeringproblemsinwhichonlythelowerandupperboundsofuncertainparametersare
required.Determiningtheboundsforanintervalcouldbeeasierandmorestraightforward
thantheidentificationofprobabilitydistributions.Therefore,intervalanalysisisappealingfor
thecaseswhenprobabilityinformationismissing.Definedastheratiosoftwocomplex-valued
randomvariables,transmissibilityfunctionsarecomplexratiorandomvariables.Directuseof
thearithmeticoperationrulesofintervalanalysistocomputecomplexintervaldivisioncan
leadtosignificantintervalexpansion,whichhindersitsrealapplicationssignificantly.Inthis
paper,weproposeanefficientalgorithmtoaddresstheissuesaforementioned.Thereciprocal
ofthedenominatoriscomputedwithmaximumaccuracybymappingcomplexintervalintoa
regionboundedbyfourcirculararcs.Asaresult,theintervaloftransmissibilityfunctionscan
beachievedbymultiplyingasmallestrectangularregioncontainingtheaboveregionwiththe
numerator.MonteCarlosimulation(MCS)isusedtoverifytheproposedscheme.Furthermore,
anumberofsamplesoftransmissibilityfunctionsobtainedfromfieldtestdataofabridgeis
usedtoverifytheaccuracyandefficiencyofthealgorithm.Resultsindicatethat,bycomparing
withthesubintervalmethod,thealgorithmisabletoefficientlysuppressintervalexpansion.
Therefore, the proposed methodology can be used to quantify the uncertainty of
transmissibilityfunctionseffectively.
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A0439- The bhattacharyya distance: a novel uncertainty quantification metric in
stochasticsensitivityanalysis
SifengBia,MatteoBroggib,MichaelBeerc
aInstituteforRiskandReliability,LeibnizUniversitätHannover,[email protected]
bInstituteforRiskandReliability,LeibnizUniversitätHannover,[email protected]
cInstituteforRiskandReliability,LeibnizUniversitätHannover,[email protected]
It has been widely accepted that uncertainties should be appropriately considered in the
campaign of verification and validation (V&V) for computational models. Uncertainty
quantification(UQ)metricsareconsequentlysignificantwiththeexpectationtoprovidean
elaboratemeasurementoftheuncertainty information.Byprovidinganabsolutegeometry
distance between two single points, the Euclidian distance is probably the most common
metric especially in deterministic model updating and sensitivity analysis approaches.
Alternatively, the Bhattacharyya distance is a stochastic metric between two samples
considering their probabilistic distributions. The Bhattacharyya distance is clearly more
comprehensiveforuncertaintytreatment,however,itsapplicationinV&Visquitelimitedin
thecurrentliteratures.Thisisnotonlycausedbyahugecalculationburdenbutalso,more
critically,causedbyitsstochasticcharacterwhenevaluatingthedistancebetweentworandom
samples.
SensitivityanalysisisakeycomponentofV&V,generallyperformedpriortomodelupdating,
with thepurpose toevaluateandrank thesignificanceofeachparameteraccording to the
quantityofinterest(QoI).Toomanyinvestigatingparametersleadstoahugecalculationcost,
andevenrenderstheupdatingoftruesignificantparametersintractable.Consequently,the
objectiveofthisworkisastochasticsensitivityanalysisapproachinwhichtheBhattacharyya
distance is perfectly embedded as UQ metric. Since the model updating process can be
deterministic or stochastic, the investigating parameters and QoI vary among various
applications. In this work, not only the parameters themselves, but also their uncertainty
characteristics,e.g.meanandvariance,areinvestigatedwiththehelpofthenovelUQmetric.
Statisticaltechniquessuchasanalysisofvarianceanddesignofexperimentsareinvolvedin
the framework so that the significance factors of the uncertain parameters are evaluated.
Feasibility of the novel UQ metric in association with the stochastic sensitivity analysis is
demonstratedinsimulationexamples.
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A0459- Modal identification of structural dynamics using sparse representation
underunderdeterminedcondition
WeiGuana,L.L.Dongb,JianYanc,J.Zhoud
aPh.D.Student,SchoolofAerospace,Xi’anJiaotongUniversity,Xi’an,China,
bAssociateprofessor,SchoolofAerospace,Xi’anJiaotongUniversity,Xi’an,China,
cPh.D.Student,SchoolofAerospace,Xi’anJiaotongUniversity,Xi’an,China,
dProfessor,SchoolofAerospace,Xi’anJiaotongUniversity,Xi’an,China,
Traditional blind source separation approaches can only handle determined or
overdetermined blind problems for operational modal identification, where the number of
observed signals is equal to or greater than active modes. When the number of observed
signals is less than active modes, new methods to undertake the underdetermined blind
conditions should be considered. This paper proposes a new modal identification method
basedonanimprovedsparsecomponentanalysis(SCA)todealwiththeunderdetermined
blind source separation problem. Firstly, an improved K-means clustering algorithm with
differentialevolutionalgorithmisintroducedtoestimatemixingmatrix(modalshapesmatrix)
usingsparsecharacteristicsofobservedmixturesignals.Havingestimatedmixingmatrix,the
modalresponsesarerecoveredviathesmoothedzero-norm(SL-0)sparserecoveryalgorithm
fromtheincompleteknowledgeofthemodalshapesmatrixandthesystemoutputresponses
intimeandfrequencydomain.Then,themodalresponsesareconvertedintotimedomainby
inverse short Fourier transform. And the modal frequencies and damping ratios can be
obtainedbyidentificationtechniqueofsingledegree-of-freedom(DOF).Finally,anumerical
simulation on discrete five DOF system shows that whether in determined or
underdetermined conditions, the proposed method can perform accurate and robust
parametersidentificationofstructuraldynamics.
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A0508-Anapproachforrobustmodelupdatingunderuncertainty
XinjieZhanga,ZhongminDengb
aXueYuanRoadNo.37,Beijing,P.R.China,SchoolofAstronautics,BeihangUniversity,
bXueYuanRoadNo.37,Beijing,P.R.China,SchoolofAstronautics,BeihangUniversity,
Increasinglyattentionhasbeenpouredintouncertaintyofmodelinrecentresearch.However,
thereisstillsomelackofknowledgeaboutrobustnessofmodelupdatingsolution.Considering
uncertaintyattributetofluctuationofdesignvariablesandnon-designvariables,anapproach
forrobustmodelupdatingisproposedinthispapertofindarobustmodelupdatingsolution.
Inthispaper,robustnessofthemodelisdefinedasthevarianceofthemodelanalyticalresult
under uncertainty. And in this method, model updating is constructed as a multi-objective
optimization problem: the first objective is the accuracy of the numerical model and the
second objective is the robustness of the model. NSGA-II algorithm is applied to solve this
multi-objectiveoptimizationproblem.Moreover,metamodelbasedonmovingleastsquare
methodisestablishedtoreducethecomputation.Twonumericalexamplesarealsoemployed
toillustratetheefficiencyoftherobustmodelupdatingmethod,andthecomparisonsbetween
robustnessmodelupdatingsolutionandtraditionalmodelupdatingsolutionunderdifferent
uncertainconditionsaremanifestedinthispaper.
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A0535-Abayesianmethodforjointparameteroptimalestimationbasedonpower
spectraldensity
YongZhanga,Yanzhaob,HuajiangOuyangc,RuijunSund
aDalian,China,DepartmentofEngineeringMechanics,StateKeyLaboratoryofStructural
AnalysisforIndustrialEquipment,DalianUniversityofTechnology,[email protected]
bDalian,China,DepartmentofEngineeringMechanics,StateKeyLaboratoryofStructural
AnalysisforIndustrialEquipment,DalianUniversityofTechnology,[email protected]
cLiverpool,UnitedKingdom,DepartmentofEngineering,UniversityofLiverpool,
dGuangzhou,China,InternationalDepartment,TheAffiliatedHighSchoolofSouthernChina
NormalUniversity,[email protected]
In this paper, A Bayesian method for joint parameter optimal estimation based on power
spectraldensityisproposedandsuccessfullyappliedtotwotypicalkindsofidentificationof
jointuncertainparameters.Aswellknown,it’sdifficulttoidentifytheuncertainparameters
accuratelybasedonfinitemeasuredresponsedatasincetheexistenceofmeasurementnoise
andmodeluncertainty.Takenthedisplacementpowerspectraldensity(PSD)asthemeasured
output,by introducingtheBayesianprobabilitymethod, the formulationof theconditional
probabilitydensityfunctionforjointparametersundermeasuredconditionsisestablished.
AndtheoptimalestimationforjointparameterscanbeobtainedviatheBayesianmaximum
posterior estimate. The proposed method exhibits excellent estimation performance and
soundrobustness.
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A0801-Joint-stiffnessidentificationoftrussbridgesusinganenhancedwatercycle
optimizationalgorithm
S.H.Mahdavia,ZexingYub,ChaoXuc
aPostdoctoralresearchfellow,SchoolofAstronautics,NorthwesternPolytechnicalUniversity,
Xi’an,China,[email protected]
bMasterstudent,SchoolofAstronautics,NorthwesternPolytechnicalUniversity,Xi’an,China,
cProfessor,SchoolofAstronautics,NorthwesternPolytechnicalUniversity,Xi’an,China,
Thepriorknowledgeonmathematicalmodelgoverningtoframestructureshasasignificant
effect on structural identification results. In addition, the dynamic behavior of frame
structuresisdirectlyrelatedtothejointrigiditiesandaccurateidentificationofthestiffness
ofstructuraljointsplaysanunderlyingroleinachievingthereliableoutcomesinstructural
conditionassessment.Thispaperpresentsarobuststrategyforjoint-stiffnessidentification
oftrussbridgesintime-domainusinganenhancedwatercycleoptimizationalgorithm.Inthat
regard,aconstitutiveformulationisdevelopedformathematicalmodelgoverningsemi-rigid
connections in truss bridges. In the model, the structural connections between frames are
modeledbyxx(asentencetoexplainthejointmodelyouused.)Then,therecentlydeveloped
watercyclealgorithm(WCA)ismodifiedtobeapplicableforjoint-stiffnessidentificationof
such structures in time-domain. For this purpose, an efficient search space reduction
technique is adopted through the optimization approach to enhance the global search
capabilityofWCA.Anexperimentalvalidationstudyiscarriedoutonalaboratoryscaledtruss
bridge. For comparison purpose, the appropriateness of the WCA in joint-stiffness
identification is thoroughly comparedwith another state-of-the-art optimization algorithm
i.e.,particleswarmoptimization(PSO).Itisconcludedthat,thecomputationalefficiencyof
the proposed strategy is significantly higher than that of PSO in dealing with rough initial
estimatesonstructuralparameters. Thisdemonstrates thesuperiorityofWCAstrategy to
handleglobalsearchoverlargedesignspacewithlargenumberofdesignvariables.Itisalso
deducedthat theproposedstrategycouldbesuccessfullyandconfidently implementedfor
damage detection in structural joints with simultaneous identification of structural
parameters. Finally, this research work was financially supported by National Science
Foundation of China NAFC’s research fund for International Young Scientist; Grant No.
51750110509andtheauthorsgreatlyacknowledgethisfinancialsupport.
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A0923-Dynamicresponseanalysisofstructureswithhybridrandomandinterval
uncertaities
YanlinZhaoa,ZhongminDengb,YongweiHanc
aSchoolofAstronautics,BeihangUniversityBeijingChina,BeihangUniversityBeijing,
bSchoolofAstronautics,BeihangUniversityBeijingChina,BeihangUniversityBeijing,
cSchoolofAstronautics,BeihangUniversityBeijingChina,BeihangUniversityBeijing,
Anoveldynamicanalysisofstructurewithhybriduncertainties(DASHU)isdevelopedforthe
expressionsforthelowerandupperboundsofthemeanvalueandstandarddeviationofthe
dynamicresponse.Withinthisapproach,intervalvariablesareadoptedtoquantifythenon-
probabilistic uncertainty associated with objective limited information. Some other
parametersareconsideredasrandomvariables.Basedonseriesexpansionofrandomand
interval quantities with respect to uncertain parameters, by means of random interval
momentmethodandperturbationtechnique,theproposedmethodevaluatethelowerand
upperbounds,themidpoint,andintervalwidthofthefirst-andsecond-ordermomentsofthe
structureresponsethroughsolvingdeterministicequations.Monte-Carlosimulationsmethod
(MCSM)areimplementedtovalidatethecomputationalresults.Finally,Numericalexamples
are analyzed to illustrate the feasibility and effectiveness of the proposed method. The
influence on the structure response caused by the individual system parameters are also
investigated.
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MS8: Computational Modeling of Damage and Failure in
Solids and Structures
A0392- Mitigating mesh dependence of stochastic computation of quasibrittle
fracture
Jia-LiangLea
aDepartmentofCivil,Environmental,andGeo-Engineering,UniversityofMinnesota
Failureanddamageofquasibrittlestructuresareoftenaccompaniedbyvariouslocalization
phenomena,whichgiverisetospuriousmeshdependenceoffiniteelement(FE)simulations.
Though extensive efforts have been devoted to developing computational approaches for
suppressingthemeshdependenceissue,theexistingeffortslargelyfocusedondeterministic
analysis. This paper will discuss the mesh dependence issue in stochastic computation of
quasibrittle fracture. I will first present a new probabilistic crack band model, which is
anchoredbyaprobabilistictreatmentofdamageinitiation,localization,andpropagation.This
model regularizes the energy dissipation of a single material element for the transition
betweendamageinitiationandlocalization.Meanwhile,themodelalsotakesintoaccountthe
randomonsetofdamagelocalizationinsidethefiniteelementforthecasewheretheelement
sizeislargerthanthecrackbandwidth.Therandomlocationofthelocalizationbandisrelated
totherandommaterialstrength,whosestatisticsisdescribedbyafiniteweakest-linkmodel.
Thesecondpartofthetalkwilldiscusstheextensionofthemodeltodynamicloading.Tothis
end,arate-dependentfiniteweakest-linkmodel isdevelopedtocapturethecombinedrate
andsizeeffectsonthestrengthdistributionofmaterialelements.Thismodelisvalidatedbya
set of stochastic discrete element simulations of aluminum nitride as a model system. The
presentresultsdemonstratethattherate-dependentfiniteweakest-linkmodelcanprovidean
analyticallinkbetweenthediscreteelementsimulationandcontinuumFEsimulation,which
leadstoapromisingmultiscalestochasticcomputationalframeworkforquasibrittlefracture.
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A0633-Phase-filedmodelingofhydraulicfracturingintheframeworkofthetheory
ofporousmedia
C.Luoa,W.Ehlersb
aPhDCandidate,InstituteofAppliedMechanics,UniversityofStuttgart,Pfaffenwaldring7,
70569,Stuttgart,[email protected]
bProfessor,InstituteofAppliedMechanics,UniversityofStuttgart,Pfaffenwaldring7,70569,
Stuttgart,[email protected]
Hydraulicfracturingisawidely-usedtechniqueintheexploitationofoilandgasresources.
Modelingtheprocedureneedstodealwiththedynamicfracturinginporousmediawhichis
of interest to a broader community including engineering geology. To address the two
challenging issues arisen from the cracking process and the multi-component aggregate, a
systematicmethodispresentedintheframeworkoftheTheoryofPorousMedia(TPM)with
thephase-fieldmodelembeddedtohandlethecrackinitializationandpropagation.TheTPM
offerseachconstituentoftheporousmediumwithanindividualmotionfunctionandhence
individual set of balance equation, and describes the coupling, i.e., the transfer of mass,
momentumandenergybetweentheindividualcomponents,usingtheso-calledproduction
terms.Thisfeaturewhencombinedwiththephase-fieldapproachallowsforthetransitionof
theDarcy-typeflowinthesaturatedporousmediadomaintowardstheNavier-Stokes-type
flowinfracturedzones.Tofurtherconsiderpre-existingclosedfracturesorfracturesclosing
aftergeneration,whereeitheronlytheDarcy-typeflowoccursorwheretheNavier-Stokes-
typeflowturnsbacktotheDarcy-typeflow,acrack-openingindicatorisproposedtoresolve
theconflictbetweenthetwo-wayflowtransitionprocessandthemonotonicevolutionofthe
phase-fieldvariable.Theestablishedmethodisthendemonstratedbynumericalresultsof2-
D and 3-D examples. The numerical results have also been compared with experimental
observationsintheliteraturewheregoodagreementisfound.
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A0757-Crackingelementsmethodforsimulatingmultiplecracks
Yiming.Zhanga,Xiaoying.Zhuangb,c
aSchoolofCivilandTransportationEngineering,HebeiUniversityofTechnology,Tianjin,
300401,China,[email protected]
bDepartmentofGeotechnicalEngineering,TongjiUniversity,Shanghai,China,
cInstituteofContinuumMechanics,LeibnizUniversitätHannover,Hannover,Germany
TheCrackingElementsMethod(CEM)isarecentlyproposednovelapproachfornumerically
simulatingquasi-brittlefracture.CEisbuiltintheframeworkofFiniteElementMethod(FEM),
which does not need remeshing, cover algorism, nodal enrichment or any specific crack
trackingstrategies.Themethodisinspiredbythestaticallyoptimalsymmetricformulation
of the strong discontinuity embedded approach (SDA-SOS) and use the standard Galerkin
method, greatly reducing the coding effort. In CE, the crack paths are represented by
disconnected cracking segments inside the cracked elements. No explicit or implicit
descriptions of the crack’s topology are needed, making the cracks as the solutions of the
considered problems but not parts of it. Comparisons of the CE’s results and the results
obtainedbysomeothermethodssuchasXFEMindicatetheeffectivenessandrobustnessof
theCEmethods,whichiscapableofsimulatingmultiplecomplexfracturepatternsandcracks.
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A0811-Stochasticanalysisofpolymercompositesrupturesatlargedeformations
modeledbyaphasefieldmethod
JieWua,ColinMcAuliffeb,HaimWaismanc,GeorgeDeodatisd
aCollegeofCivilEngineering,HebeiUniversityofTechnology,Tianjin,China,[email protected]
bDepartmentofCivilEngineeringandEngineeringMechanics,ColumbiaUniversity.NewYork,US
cDepartmentofCivilEngineeringandEngineeringMechanics,ColumbiaUniversity.NewYork,US
dDepartmentofCivilEngineeringandEngineeringMechanics,ColumbiaUniversity.NewYork,US
Carbonblackreinforcednaturalrubberisacompositematerialthatisincreasinglybeingused
inengineeringapplications.Detailedknowledgeoftherelationshipbetweenthecomposition
ofreinforcedrubberanditsfracturetoughnessisimportantforanalysisanddesignofvarious
engineeringsystems.Tothisend,theArruda-Boycemodelisadoptedformodelingthehyper-
elasticrubbermatrixandaNeo-Hookeanmodelisusedforthereinforcingparticles.Aphase
fieldmethodisthenemployedtosimulatedamagenucleationandpropagationunderquasi-
staticloading.Thephasefieldhyper-elasticmodelisvalidatedonasetofexperimentaldata
availableintheliterature.Toquantifytheuncertaintyinthefailureofthesematerials,aMonte
Carlosimulationiscarriedoutwithrandomellipsoidalparticlesdistribution.Eachrealization
undergoeslargestretchinguptofailure,whereforcedisplacementcurvesandfracturesurface
energiesarerecorded.Failureofasampleisdefinedasthepointwheretheloaddropstothe
75%ofthepeakforce.Numericalexamplesofstiffinclusionsandvoidsareconsideredand
the composite response is examined on an intact and pre-notched unit cells. A rigorous
stochastic analysis reveals the statistical distributions corresponding to the rupture of
polymercompositesandprovidesinsightintobetterdesignofthesematerials.
Figure1Stretchandruptureofapolymercompositeatlargedeformation
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MS9: Reliability Analysis of Engineering Structures
under Disastrous Excitations
A0022-Aprobabilisticanalysisofaphenomenologicalmodelforstructuralcollapse
simulation
ChengChena,b,YifengXuc
aSchoolofEngineering,SanFranciscoStateUniversity,SanFrancisco,CA94132
bSchoolofCivilEngineering,ShandongUniversity,Jinan,Shandong,China
cSchoolofEngineering,SanFranciscoStateUniversity,SanFrancisco,CA94132
The modified IMK model provides a powerful phenomenological model for collapse
simulationofstructuresbyreproducingnonlinearstiffnessandstrengthdegradationinthe
elementsduetorepeatedcyclesofloading.Theaccuracyofcollapsesimulationdependson
realisticcharacterizationofmodelparameters.Modelparametersderivedfromexperiments
however have inherent uncertainties due to optimization. Collapse simulation based on
deterministicparametervaluesofthemodifiedIMKmodelmightnotprovidereliableestimate
ofriskforcollapseduetotheseparameteruncertainties.Inthisstudy,themodifiedIMKmodel
is evaluated through probabilistically characterizing the model parameters based on three
quasi-staticcyclictestsoffull-scalebeam-columnconnectionsconductedpreviouslyatLehigh
University. The Metropolis-Hasting algorithm is utilized to derive the statistics of model
parametersandcomparewiththeirdeterministicvalues.Computationalsimulationsarethen
conductedtoevaluatetheeffectofmodeuncertaintyintermsofenergydissipation.
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A0347-Simulationofstationarynon-gaussianvectorprocesswithinwave-passage
effectbasedonspectralrepresentationmethod
YongxinWua
aAssociateProfessor,KeyLaboratoryofMinistryofEducationforGeomechanicsand
EmbankmentEngineering,HohaiUniversity,No.1,XikangRoad,Nanjing,China,
Wave-passageeffectisalwaysofgreatimportancewhenperformingthedynamicanalysisof
lagerscalestructures.ThiseffectcanbeeasilyconsideredinthesimulationofGaussianvector
process,butthereisnotanefficientwaytointroduceitintothenon-Gaussianvectorprocess.
Inthispaper,amethodisproposedtogeneratestationarynon-Gaussianvectorprocesswithin
wave-passage effect. In the simulation of vector process, wave-passage effect leads to a
complex-definedcrossspectraldensitymatrix(CSDM).Toseparatethephasepartfromthe
CSDM,animprovedformofspectralrepresentationmethod(SRM)isproposed,inwhichthe
phasepartrepresentingthewave-passageeffectcanbedirectlyexpressedinanexplicitform
in the simulation formula. Then the characteristic of phase part representing the wave-
passage effect during the nonlinear translation (translating underlying Gaussian vector
processtotheprescribednon-Gaussianvectorprocess)is investigated.It isfoundthat,the
phase part is not changed. Based on this good feature, the modified SRM and the iterative
schemecanbecombinedtosimulatenon-Gaussianvectorprocesswithinwave-passageeffect.
Two examples, involving the simulation of seismic ground motions and wind velocity time
histories,arepresentedtoshowthegoodfeatureaswellasthecharacteristicsofthesimulated
vectorprocess.
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A0349- Stochastic dynamic response analysis and reliability assessment of non-
linearstructuresunderfullynon-stationarygroundmotions
JunXua,De-chengFengb
aAssociateprofessor,CollegeofCivilEngineering,HunanUniversity,Changsha,P.R.China,
bAssistantprofessor,KeyLaboratoryofConcreteandPrestressedConcreteStructuresofthe
MinistryofEducation,SoutheastUniversity,2Sipailou,Nanjing210096,China
In this paper, stochastic dynamic response analysis and reliability assessment of nonlinear
structuresunderfullynon-stationarygroundmotionsisinvestigatedbasedontheprobability
density evolution method (PDEM). To handle this problem, a new method is proposed for
pointsselectioninhigh-dimensionalrandom-variatespaceforPDEM,whichisofparamount
importance for the tradeoff of accuracy and efficiency. First, the original high-dimensional
space is decomposed into several two-dimensional orthogonal subspaces. Then, each
subspace is partitioned via the Voronoi cells and the representative points and assigned
probabilitiesineachsubspacearespecifiedaccordingly.Finally,therepresentativepointsand
assignedprobabilitiesineachsubspacearerandomlypairedtoformulatetherepresentative
pointsandassignedprobabilitiesinhigh-dimension.Numericalexampleisstudiedtovalidate
theproposedmethod,whichindicatesthattheproposedmethodisofefficiencyandaccuracy
forhigh-dimensionalstochasticdynamicproblemofstructures.Problemneedstobefurther
investigatedisalsopointedout.
Engineering Mechanics Institute
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113
A0403- Integrated reliability-based optimization of civil structure and vibration
controlsystemsusingimprovedgeneticalgorithms
ZhenMeia,HaifengWangb
aLecturer,HuaqiaoUniversity,[email protected]
bLecturer,HuaqiaoUniversity,[email protected]
Disastrousexcitationssuchassevereearthquakesandstrongwindsposeagreatthreattocivil
engineering structures. To improve the safety and serviceability of structures excited by
external dynamic loads, significant efforts have been devoted to the investigations on
structuralvibrationcontrol.Variouscontrolstrategies,includingpassive,active,semi-active
and hybrid control systems, have been proposed and many control devices, like rubber
bearings, buckling constraint supports, magnetorheological dampers and so on, have been
developedandappliedtocivilstructures.Ithasbeenproventhatactive/semi-activecontrol
effectsaresimultaneouslyrelatedtoinputdynamicactions,controlalgorithms,thenumber
and location of actuators / dampers and physical parameters of controlled structures.
Therefore,itisnecessarytoconducttheoptimizationofthecontrolsystemandthecontrolled
structure as a whole. In this paper, an improved genetic algorithm is developed to solve
reliability-basedoptimizationproblemsforcivilstructureandactivecontrolsystems,inwhich
thenumberandpositionofactuators,thecontrolalgorithm,thestructureparameterandthe
randomness of seismic excitations are taken into account synchronously. The optimization
objectivefunctionisthefailureprobabilityofthecontrolledstructureandthefirstexcursion
failure criterion is used in dynamic reliability analysis. Moreover, the reliability of the
controlledstructureisdefinedbyinter-storydriftanglesandisperformedusingthetheoryof
extreme value distribution and the probability density evolution method. In addition, a
selection policy, which is a combination of random competition and elitist strategy, an
improvedbinarysingle-pointcrossoverandanimprovedsingle-locusortwo-locusmutation
are adopted in the developed genetic algorithm. Results of numerical examples conducted
using MATLAB software show that the proposed algorithm has the advantages of high
precisionandfastconvergence,thusitisaneffectiveintegratedoptimizationmethodforcivil
structureandvibrationcontrolsystems.
Engineering Mechanics Institute
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A0520-Seismicfragilityanalysisofurbanroadnetwork:acasestudyontangshan
city
DingWanga
aAssociateprofessor,YanshanUniversity,[email protected]
Recently, many studies have analyzed the vulnerability of the components of the roadway
transportationsystem,suchasembankment,cut,slopeandroadpavement,underearthquake
attack. However, the seismic fragility analysis of the roadway network has not been fully
investigatedorappliedinengineeringpractice.Inthisstudy,aframeworkforanalyzingthe
seismic fragility of the urban roadway network is presented and used for the roadway
transportation system in Tangshan City, China. This approach is based on the Monte-Carlo
method.Thespatialvariationoftheseismicgroundmotionsisconsidered.Bytheproposed
approach, the seismic performances of the roadway network under earthquake attacks of
differentintensityispresentedanddiscussed.Thepresentstudyshowsthat,forTangshanCity,
theconnectivityoftheurbanroadwaynetworkcanbewellmaintainedwhentheaveragepeak
groundacceleration(PGA)ofthespatiallyvariableseismicgroundmotionsislessthan0.25g.
ThepresentworkalsoadvocatesthatwhenthePGAislargerthan0.55gthegiantcomponent
oftheroadwaynetworkisdamagedandtheroadwaytransportationsystemtotallylossesits
functionality.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0538- Impact of initial damage path and spectral shape on aftershock collapse
fragilityofRCframes
Xiao-HuiYua,Da-GangLub,Fu-ZiMac
aSchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,P.R.China,
bSchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,P.R.China,
cSchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,P.R.China,
Theinfluencesofinitialdamagepathsandaftershock(AS)spectralshapeontheassessment
ofAScollapsefragilityareinvestigated.Todothis,afour-storyductilereinforcedconcrete(RC)
framestructureisemployedasthestudycase.Thefar-fieldearthquakerecordsrecommended
by FEMA P695 are used as AS ground motions. The AS incremental dynamic analyses are
performedforthedamagedstructure.Toexaminetheeffectofinitialdamagepaths,atotalof
sixkindsofinitialdamagepathsareadoptedtosimulatedifferentinitialdamagestatesofthe
structurebypushoveranalysisanddynamicanalysis.Forthepushover-basedinitialdamage
paths, the structure is “pushed” using either uniform or triangle lateral load pattern to a
specifieddamagestatequantifiedbythemaximuminter-storydriftratio.Amongthedynamic
initialdamagepaths,onesinglemainshockgroundmotionorasuiteofmainshockground
motionsareusedintheincrementaldynamicanalysestogenerateaspecifiedinitialdamage
statetothestructure.Theresultsshowthatthestructurecollapsecapacityisreducedasthe
increase of initial damage, and the initial damage paths show a significant effect on the
calculatedcollapsecapacitiesofthedamagedstructure(especiallyatseveredamagestates).
To account for the effect of AS spectral shape, the AS collapse fragility can be adjusted at
differenttargetvaluesofεbyusingthelinearcorrelationmodelbetweenthecollapsecapacity
(intermofspectralintensity)andtheASεvalues,andcoefficientsofthislinearmodelisfound
tobeassociatedwiththeinitialdamagestates.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
116
A0563-Structuralreliabilityanalysisusinguqfemsoftware
ZiqiWanga,SanjayGovindjeeb,NikhilPadhyec,FrankMcKennad
aAssistantProfessor,GuangzhouUniversity,[email protected]
bProfessor,UniversityofCalifornia,Berkeley,[email protected]
cPostdoctoralResearcher,UniversityofCalifornia,Berkeley,[email protected]
dSeniorScientist,UniversityofCalifornia,Berkeley,[email protected]
In this talk, we will illustrate the usage of uqFEM, a software for driving uncertainty
quantification in finite element and other analysis programs, with special emphasis on
structural reliability applications. Recently developed by SimCenter
(https://simcenter.designsafe-ci.org/)atUniversityofCalifornia,Berkeley,uqFEMisanopen
source software tool that allows engineers to perform reliability-based computations for
naturalhazardsandriskassessment.Inthetalktheusabilityandcapabilitiesoftherelease
version of uqFEM will be illustrated with numerical examples on benchmark structural
reliabilityproblemsincludingtaildistributionestimation.Toconcludethetalk,newfeatures
anduncertaintyquantificationalgorithmsplannedforfuturereleaseswillbediscussed.
Engineering Mechanics Institute
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A0577- Seismic reliability analysis of energy-dissipation bridge structures using
HamiltonianMonteCarlobasedsubsetsimulationinconjunctionwithexplicittime
domaindimensionalityreduction
HaitaoMaa,ShaominJiab,ZiqiWangc,WeimingChend
aEarthquakeEngineeringResearch&TestCenter,GuangzhouUniversity,Guangzhou,China
bEarthquakeEngineeringResearch&TestCenter,GuangzhouUniversity,Guangzhou,China
cEarthquakeEngineeringResearch&TestCenter,GuangzhouUniversity,Guangzhou,China
dEarthquakeEngineeringResearch&TestCenter,GuangzhouUniversity,Guangzhou,China
The seismic reliability analysis of energy-dissipation bridge structures is typically a local
nonlinearproblem,sinceenergydissipationdevicesareofteninstalledinspecificlocationsof
abridgestructure.TheMonteCarlosimulation(MCS)methodhastheapplicabilitytosolve
genericnon-linearreliabilityproblems,yetthecomputationalcostofMCSisoftentoohighfor
engineeringpractice.ThecomputationalefficiencyofusingMCStoperformseismicreliability
analysisisdeterminedbytheefficiencyofthespecificMCSschemeaswellastheefficiencyof
asinglerunofdeterministicnonlinearstructuraldynamicanalysis.Thepaperproposesan
efficientcomputationalmethodforseismicreliabilityanalysisofenergy-dissipationbridges
via the usage of: a) Hamilto-nian Monte Carlo based subset simulation to improve the
sampling efficiency, and b) an explicit time domain dimensionality reduction technique to
improve the efficiency of deterministic struc-tural dynamic analysis of local nonlinear
problems.Numericalexamplesofbridgemodelsareinvestigatedtoillustratetheefficiencyof
theproposedapproach.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
118
A0824-Assessingthespallingoftunnelliningssubjectedtofireloading
Yiming.Zhanga,Matthias.Zeimlb,Marcus.Maierc,Yong.Yuand,Roman.Lacknere
aSchoolofCivilandTransportationEngineering,HebeiUniversityofTechnology,Xiping
Road5340,300401Tianjin,China,e-mailaddress:[email protected]
bMaterial-TechnologyInnsbruck(MTI),UniversityofInnsbruck,Technikerstraße13,6020
Innsbruck,Austria
cMaterial-TechnologyInnsbruck(MTI),UniversityofInnsbruck,Technikerstraße13,6020
Innsbruck,Austria
dDepartmentofGeotechnicalEngineering,TongjiUniversity,SipingRoad1239,200092
Shanghai,China
eMaterial-TechnologyInnsbruck(MTI),UniversityofInnsbruck,Technikerstraße13,6020
Innsbruck,Austria
Spallingistheviolentsplittingofconcretepiecesfromthefire-loadedsurface,whichgreatly
jeopardizes the integrity of the structures. Fires in tunnels commonly lead to a fast
temperatureincreaseduringthefirstminutesofthefirewithamaximumtemperatureover
1200°C,potentiallyresultingintoseriousspalling.Bydevelopingandapplyingafullycoupled
thermo-hydro-chemo-mechanicalmodel,wefirstlyanalyzethespallingoffireloadedplate-
likestructures.Then,weestablishafastassessingprocedureforquicklyevaluatingspalling
riskoftunnelliningswithdifferentconcretetypesandenvironmentalmoisturesandpropose
criterion for grading the spalling risk. Comparisons between the obtained results and
experimental results prove the effectiveness of our methods, which can be used by the
engineersanddesignerforassessingthefirespallingriskofconstructedandplanedtunnel
structures.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
119
MS10: Damage and Fracture of Brittle and Quasi-Brittle
Materials
A0034- Influenceofasphaltmixture typeonstrengthsizeeffectstatisticsat low
temperature
AugustoCannoneFalchettoa
aAssistantProfessor,DepartmentofCivilEngineeringandEnvironmentalScience,
TechnischeUniversitätBraunschweig,Germany,[email protected]
Low temperature cracking represents a deleterious phenomenon for asphalt pavement
experiencingcoldclimates.Hence,accurateevaluationofstrengthandfracturepropertiesof
asphaltmixturesiscriticalforensuringthedurabilityoftheentirepavementstructure.Itwas
recentlydemonstratedthat,at lowtemperature,asphaltmixturesbehaveasaquasi-brittle
materialand,consequently, itsnominalstrengthstronglydependsonstructuresize.Inthis
paper,acomprehensiveexperimentalstudyisconductedtoevaluatetheeffectofmixturetype
onthescalinglawforquasi-brittlestrength.Astandardasphaltmixtureforwearingcourse
andaStoneMasticAsphalt(SMA)areselectedforthispurpose.Three-pointbendingtestsare
performedonunnotchedasphaltmixturebeamsoffourdifferentsizesat lowtemperature.
ThestrengthvaluesareevaluatedbasedontheWeakestLinkModel(WLM)incombination
withthewell-knownTypeIenergetic-statisticalsizeeffectlaw(SEL).Asignificantvariation
intheevolutionoftheSELisobservedwithadramaticdecreaseinstrengthoversize.The
effect of mixture type indicates a significant influence on the statistics of strength with an
increase of the grafting point in the cumulative distribution function of the representative
volume element (RVE) for SMA. This is linked to an increased brittleness, which is overall
compensatedbythemodifiedbinderusedforthisspecificmixtureandbythehighermaterial
strength. The experimental and modeling results clearly demonstrate the importance of
understanding the scaling evolution of asphalt mixture strength since this parameter is
commonlyusedasinputforpavementdesignpurposes.
Engineering Mechanics Institute
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120
A0857-Modellingofdamageandfractureofplainweaveceramicmatrixcomposites
underuni-aixaltension
DaxuZhanga,MingmingChenb,HailongLiuc,YunhaoZhangd
aAssociateProfessor,SchoolofNavalArchitecture,OceanandCivilEngineering,Shanghai
JiaoTongUniversity,China,[email protected]
bPhDCandidate,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
cMScCandidate,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
dMScCandidate,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
Ceramicmatrixcomposites(CMCs)havethecharactersoflowdensity,highmodulusandgood
thermalstability.Overthepastdecades,greateffortshavebeenmadetostudythemechanical
behaviourofCMCs.Amongthem,ZhangandHayhurst(2010)[DaxuZhang,HayhurstDR.,
2010. Stress-strain and Fracture Behaviour of 0°/90° and Plain Weave Ceramic Matrix
CompositesfromTowMulti-axialProperties.InternationalJournalofSolidsandStructures.
47(21).2958-2969.]employedahomogenisedfiniteelementmodeltostudystress-strainand
fracturebehaviourofcross-plyandwovenCMCs.Onthebasisofthiswork,anon-linearmulti-
scalemodelhasbeendevelopedtopredictstress-strainresponseofplainweaveCMCsunder
in-planeloading.Acontinuumdamagestateparameterdeterminedbytheratiooffailedfibres
and total fibres was used to evaluate the longitudinal tensile behaviour of a unidirectional
fibre-reinforcedCMCtow.Theseanalyticalresultsoffibretowswerethenemployedbyafinite
elementplainweaveCMCunitcellmodelasthematerialproperties,inwhichthetensileand
shearpropertiesof towswerenonlinearandweredefinedbyauserdefinedsubroutine in
Abaqus.APythonscriptwasdevelopedtodefinetheperiodicboundaryconditionsoftheunit
cell. The uni-axial tensile stress-strain response has been predicted using the multi-scale
model. The fidelity of the model has been verified by comparing its predictions with the
experimentalresults.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0863-Predictionofsheardamagebehaviourof fibre-reinforcedceramicmatrix
tows
DaxuZhanga,QianXub,YunhaoZhangc,HailongLiud
aAssociateProfessor,SchoolofNavalArchitecture,OceanandCivilEngineering,Shanghai
JiaoTongUniversity,China,[email protected]
bResearchAssistant,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
cMScCandidate,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
dMScCandidate,SchoolofNavalArchitecture,OceanandCivilEngineering,ShanghaiJiao
TongUniversity,China,[email protected]
Ceramicmatrixcomposites(CMCs)havethecharactersoflowdensity,highmodulusandgood
thermalstability.Overthepastdecades,greateffortshavebeenmadetostudythemechanical
behaviourofCMCs.However,arigorousframeforunderstandingnonlinearshearbehaviorof
CMCs on both microscopic and macroscopic level is lacking. Nevertheless, it is generally
acceptedthatmatrixcrackingisthemaindamagemechanismwhichgovernstheshearstress-
strainresponseofCMCs. In thispaper,amodelbasedonasinglecontinuumdamagestate
parameterdeterminedbytheratioofthecurrentmatrixcrackdensityandsaturateddensity,
hasbeendevelopedtopredicttheshearbehaviourofaunidirectionalfibre-reinforcedceramic
matrix composite (CMC) tow. The model considers the influence of matrix cracking using
Weibull distributions of damaged matrix shear strength. The nonlinear shear stress-strain
response of a CMC tow, predicted by the damage model, has been used in a macro-scale
analysistoevaluateitsfidelity.
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A0866- Validation of the combined fem-dem on mode i and ii concrete rupture
subjectstosemi-circularbending
XudongChena
aLecturer,SuzhouUniversityofScienceandTechnology,[email protected]
Tovalidatetheeffectivenessof thecombinedFEM-DEMundercomplex loadingconditions,
simulationsareperformedandresultsarecomparedwithknownsemi-circularbending(SCB)
tests based on concrete aggregate specimen with pre-existing notches. A bilinear strain-
softeningcurvewhichisimplementedintoacohesivefracturemodelisadoptedtodepictthe
behavior from continua to discontinua. A constant displacement rate is applied to the top
center of the specimen. By comparing the simulation results from the FEM-DEM and the
experimentaldatafromknownSCBtests,conclusionsarereachedthatthecombinedFEM-
DEMtogetherwiththecohesivefracturemodelcanpredictbothMode-IandII failurewith
goodaccuracy.ForMode-Ifracture,adominantflexuralcrackisobtainedfromthenotchtip
uptotheloadingpoint.Ontheotherhand,anobliquecrackisformedforMode-IIfracture,
approximatelylinkingtheloadingpointandthenotch.Ingeneral,thecombinedFEM-DEMis
applicableofsimulatingModeIandIIfractureofconcreteSCBspecimen.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
123
A0978-Impactfracturesimulationofmonolithicandlaminatedglassusinghybrid
discontinuaandcontinuamethod
Xing-erWanga,JianYangb
aPostdoc,DepartmentofCivilEngineering,ShanghaiJiaoTongUniversity
bProfessor,DepartmentofCivilEngineering,ShanghaiJiaoTongUniversity,
Thisworkpresentsacomparativestudyontheavailablenumericalapproachesformodelling
thefracturingofbrittlematerials,e.g.glassandrock.Thesemodellingtechniquesincludefour
popularnumericalmethodssuchasthefiniteelementmethod(FEM),extendedfiniteelement
method (XFEM), discrete element method (DEM) and combined finite-discrete element
method (FEM/DEM). This study investigates their inherent weaknesses and strengths for
modelling the fracture and fragmentation process both in static and dynamic problem. A
comparativereviewisfirstcarriedouttoillustratetheirfundamentalprinciplesaswellasthe
advantages for the modelling of cracks, followed by state-of-the-art trial application in the
example cases. Several examples of a glass beam subjected to low velocity impact are
examinedusingaforementionednumericalmethodsasaplanestressproblem.Byevaluating
their applicability, the most feasible model, i.e., FEM/DEM, for the entire dynamic fracture
response is identified. It is further examined comparing with the experimental results for
modellingthehighspeedandobliqueimpacttestsonglasssurface.Throughsuchcomparative
study, the FEM/DEM exhibits the most satisfactory results when modelling the dynamic
fracture of brittle materials with specific reference to glass. It also shows potential in
simulatingthecompositeactionbetweenductileinterlayerandbrittleglassinthelaminated
glass.TheMooney-RivlinmodelforthehyperelasticityofthePVBinterlayersaswellasthe
improvedXuandNeedlemanmodelservingasthemixed-modeinterfacialconstitutivelaw,in
particular, describing the combined damage-plasticity behaviour for irreversible unloading
arethenimplementedintoFEMDEM.Theimpactdamageoflaminatedglassin2Dproblem
including the interlaminardelaminationandcrackpattern is thenexaminedby using such
integratedapproachesThecomparisonbetweenthesimulationandtheexperimentalresults
for several laminated glass make-ups shows that this interfacial model can adequately
reproduce the typical delamination behaviour. The characteristics of the stress wave
propagationandtheinterlayertearingintheexamplecasescanbesatisfactorilyreproduced.
Theshortcomingofthediscretecrackmodelinmodellingtheimpactdamageofstrengthened
glass and the resulting errors are discussed as well. Several potential solutions for such
shortcomingsarefinallypresented.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
124
MS12: Dynamic Analysis and Seismic Performance of
Structures under Strong Earthquake Ground Motions
A0008- Potential risks on using disconnected composite foundation systems in
activeseismiczones
MohamedElmasrya,AhmedRaghebb,TareqMostafac,MohamedGhazyd
aProfessor,ArabAcademyforScience,Technology&MaritimeTransport,[email protected]
bAssociateDoctor,ArabAcademyforScience,Technology&MaritimeTransport,
cAssociateDoctor,ArabAcademyforScience,Technology&MaritimeTransport,
dTeachingAssistant,ArabAcademyforScience,Technology&MaritimeTransport,
Choosingthesuitableinfrastructuresystemisbecomingmorechallengingwiththeincrease
indemandforheavierstructurescontemporarily.Thisisthecasewherepiledraftfoundations
have been widely used around the world to support heavy structures without extensive
settlement.Inthelattersystem,pilesarerigidlyconnectedtotheraft,andmostoftheload
goestothesoillayeronwhichthepilesarebearing.Inspiteofthat,whensoilprofilescontain
thickersoftclaylayersnearthesurface,oratrelativelyshallowdepths,itisunfavourableto
usetherigidpiledraftfoundationsystem.Consequently,thedisconnectedpiledraftsystem
wasintroducedasanalternativeapproachfortherigidlyconnectedsystem.Inthissystem,
pilesaredisconnectedfromtheraftusingacushionofsoil,mostlyofagranularinterlayer.The
cushionisusedtoredistributethestressesamongthepilesandthesubsoil.Pilesarealsoused
tostiffenthesubsoil,andbythiswayreducethesettlementwithoutbeingrigidlyconnected
to the raft. However, the seismic loading effect on such disconnected foundation systems
remainsaproblem,sincethesoilprofilesmayincludethickclaylayerswhichraiserisksof
amplificationofthedynamicearthquakeloads.Inthispaper,theeffectsofseismicbehavior
ontheconnectedanddisconnectedpiledraftsystemsarestudiedthroughanumericalmodel
using Midas GTS NX Software. The study concerns the soil-structure interaction and the
expectedbehaviorofthesystems.AdvantagesandDisadvantagesofeachfoundationapproach
arestudiedandacomparisonbetweentheresultsarepresentedtoshowtheeffectsofusing
disconnected piled raft systems in highly seismic zones. This was done by showing the
excitationamplificationineachofthefoundationsystems.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
125
A0016-Output-onlyidentificationofcivilengineeringsystems
ErtugrulTaciroglua,S.FaridGhaharib
aProfessor,CivilandEnvironmentalEngineeringDepartment,UCLA,USA,[email protected]
dPostdoctoralResearchAssociate,CivilandEnvironmentalEngineeringDepartment,UCLA,
Formechanicalsystemsandlaboratory-scalestructures,itisusuallypossibletoarrangeand
carry out dynamic tests. Typically, the same is not possible for full-scale civil engineering
systems (bridges, buildings, dams, tunnels, geotechnical arrays, etc.). As such, responses
measured during natural events (earthquakes, hurricanes, etc.) provide the only means to
examinestructuralresponsesinthemostrealisticmannerpossible.Theseexaminationshave
multiple utilities, ranging from the development and validation of predictive models—
including the characterization of uncertain loads—to health and performance monitoring.
However,thesenaturallygeneratedexcitationsarerarelymeasurable,renderingtherequisite
identificationproblemstobeill-posedforwhichboththesystemandtheinputexcitationsare
unknown. For example, a building (or bridge) under its operational condition is usually
persistently excited by ambient loads that are not measurable (like micro-tremors, ocean
waves, people, car traffic, etc.). Or, it is not possible to record true seismic excitations to a
buildingstructure,becauseeventhemotionsrecordedatthefoundationlevelarenotpurely
input,duetoinertialeffects.Althoughvariousoutput-onlysystemidentificationmethodshave
been developed during the past few decades, they mostly adopt various simplifying
assumptionsregardingthestatisticalcharacteristicsoftheunknowninputexcitations—the
primaryassumptionbeingthestationarityoftheunknowninput.Nevertheless,mostreal-life
casesdonotfallintothissimplification,andthustheidentifieddynamiccharacteristicscan
have large errors. Over the past decade, the authors have been working towards the
development of novel and robust output-only techniques to resolve deficiencies associated
with these traditional output-only methods. In this paper, a comprehensive survey of their
methods—ranging from model-free Blind Modal Identification (BMID) methods to model-
basedBayesianfilteringtechniques—arepresented,alongwiththeapplicationofthesenew
techniquestoreal-lifeengineeringproblems.
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International Conference 2018 November 2-4 Tongji University
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A0024-Analysisofthebridgewithsinglecolumnbyperformanceandreliability-
basedseismicdesignmethod
XiangYiqianga,LuoXiaofengb
aProf.,DepartmentofCivilEngineering,ZhejiangUniversity,[email protected]
bAssociatedProf.,SchoolofCivilEngineeringandArchitecture,ZhejiangIndustry
PolytechnicCollege,[email protected]
Theprobabilitylimitstatedesignmethodbasedonreliabilityisoneofthestructuraldesign’s
basicprinciples,Anewgenerationstructuralseismicdesignmustbasedonperformance,it
shouldconsidertheinfluenceofrandomfactors.Combiningwiththeabovetwoaspects,this
paperstudiestheseismicreliabilityanalysismethodforthebridgeswithsinglecolumnunder
differentseismicfortificationlevelsbasedonperformanceandreliability.Thekeypointsand
flow chart of theoretical analysis methods of seismic reliability under different seismic
fortification levels are described and given. Taking the bridges with single column as an
example, thethree-dimensionalspacemodel isestablishedbyOpenseesplatform.Thepier
and the whole bridge system’s reliability are analyzed under different seismic inputs and
performancelevelsbyProbabilityPushoverMethod(PPM).Comparedwiththevaluesgained
byusingnonlinearStochasticFiniteElementMethod(SFEM),theresultsshowthatthefailure
probability values gained by using nonlinear SFEM and PPM are basically identical, bridge
system’sfailureprobabilityisgreaterthanasinglecomponent’sfailureprobabilityunderthe
actionofearthquake.Itcanbewidelyusedinbridge'sseismicdesign.
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A0105- Dimensional seismic responses of shear-flexural beam and self-similar
interstorydriftspectrum
GuiqiangGuoa,DixiongYangb
aPhDstudent,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,State
KeyLaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
dProfessor,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,StateKey
LaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
This paper investigates the influence of stiffness reduction along height on the seismic
responses of shear-flexural beams subjected to near-fault ground motions by using
dimensionalanalysistheory,andproposesaregressionmodelfortheself-similarinterstory
drift spectrum and self-similar floor acceleration spectrum. The stiffness along structural
height is always nonuniformly distributed in realistic buildings, which is not sufficiently
consideredintheseismicresponseanalysisofshear-flexuralbeamssubjectedtonear-fault
ground motions. This paper systematically analyzes the dimensional seismic responses of
shear-flexuralbeamswithnonuniformstiffnessalongheight,whereinbothanalyticalpulses
andrealisticgroundmotionsareconsidered.Thenormalizedresponsesareself-similartothe
pulseamplitudeandnormalizedstructuralheight.Itisshownthattheself-similarinterstory
drift spectrum is affected by the lateral stiffness ratio of top to base end of shear-flexural
beams.Incontrast,theself-similarflooraccelerationspectrumisalmostnotinfluencedbythe
lateralstiffnessratiooftoptobaseendofshear-flexuralbeams.However,theeffectofstiffness
reductionisgenerallysmallandhencecanbeneglectedinthepreliminarydesignofbuildings.
Aproposedregressionmodelissuitablefortheself-similarinterstorydriftspectrumandself-
similar floor acceleration spectrum, which can predict maximum interstory drift ratio and
maximumflooraccelerationwithacceptableaccuracy.
Engineering Mechanics Institute
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A0109- A new approach to design explicit time integration algorithm with
numericaldissipation
ShiLia,HongjiaZhangb,DixiongYangc
aPhDstudent,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,State
KeyLaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
bMaster,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,StateKey
LaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
cProfessor,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,StateKey
LaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
Thepseudodynamictestingandreal-timehybridtestinginearthquakeengineeringrequire
the fast and accurate dynamic analysis of structure. To develop the stable, accurate and
efficienttimeintegrationalgorithmsistheimportantresearchtopic.Thispaperproposesa
familyofexplicittimeintegrationalgorithmsforstructuraldynamicsbyutilizingtheseparate-
designconcept.
Thetraditionaltimeintegrationalgorithmusestheequationofmotionandonesetofrecursive
formulaofvelocityanddisplacementtosolvethedynamicresponseofsystem.However,the
new separate-design approach adopts two sets of recursive formula of velocity and
displacement.Onesetofrecursiveformulaofvelocityanddisplacementiscombinedwithand
the motion equation to obtain the recursive formula of acceleration, and another set of
recursiveformulaofvelocityanddisplacementisutilized.Asaresult,therecursiveformulaof
acceleration,displacementandvelocityareachievedseparately.Theformulationcoefficients
of new algorithm adopt the structure-dependent parameters. The values or ranges of
integration parameters are derived by making constraint conditions to meet the desired
numerical properties. Further, the parameters are function of the spectral radius ρ, which
controlsthenumericaldamping.Theoreticalanalysisindicatesthatthenewproposedexplicit
time integration algorithms possess the properties of second accuracy, self-starting, non-
overshoot behavior for zero-order displacement and zero-order velocity response,
unconditionallystableandcontrollablenumericaldamping.Moreover,theCRalgorithmand
KR-α method are special case of the new explicit algorithms. Finally, numerical examples
demonstrate that the accuracy of new algorithms is superior to that of Generalized-α
algorithms.Theexplicittimeintegrationalgorithmsareappliedtosolvenonlineardynamic
responsesofstructures,whichverifiestheeffectivenessandstabilityofthenewalgorithms.
Engineering Mechanics Institute
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A0112- Recent advances in engineering characteristics of near-fault ground
motionsandseismiceffectsofbuildingstructures
DixiongYanga,GuohaiChenb
aProfessor,DepartmentofEngineeringMechanics,DalianUniversityofTechnology,StateKey
LaboratoryofStructuralAnalysisforIndustrialEquipment,Dalian,China,
Severedamagesofcivil infrastructuresundernear-faultgroundmotionshave impelledthe
community of earthquake engineering to pay close attention and investigation to their
engineering characteristics and structural seismic effects. This paper reviews the recent
researchadvancesofauthorsintheengineeringcharacteristicsofnear-faultgroundmotions
andseismicresponsesandbase-isolatedperformanceanalysisofbuildingstructures.Firstly,
twonon-structure-specificintensityparameters,suchasimprovedeffectivepeakacceleration
andvelocity(IEPA,IEPV)wereproposed.Twofrequencycontentparametersweresuggested,
namely the mean period of Hilbert marginal spectrum Tmh and coefficient of variance of
dominant instantaneous frequency of Hilbert spectrum Hcov which reflects the frequency
nonstationarydegreeofgroundmotions.Meanwhile,anewstochasticmodel tosynthesize
near-faultimpulsivegroundmotionswiththefeatureofthestrongestpulsewasestablished.
Then, the chaotic and fractal/multifractal characteristics of strong earthquake ground
motions were analyzed deeply to explore their complexity from a novel perspective of
nonlinear dynamics, and the inherent relation between fractal dimensions and period
parameters of near-fault motions was exposed. Moreover, the mechanism of interstory
deformationoftallbuildingwasillustratedbasedontheengineeringpropertiesofimpulsive
ground motions and generalized drift spectral analysis. Dimensional responses analysis of
elastoplastic structures and self-similar response spectrum are presented. Finally, the
influences of ground motion properties on the seismic responses and performance of tall
structuresandbase-isolatedbuildingswererevealed.
Engineering Mechanics Institute
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A0293- Optimal design of sma cable restrainers for seismic protection of a lrb
isolatedsimplysupportedhighwaybridge
ShuaiLia,FarshadHedayatiDezfulib,Jing-quanWangc,M.ShahriaAlamd
aKeyLaboratoryofConcreteandPrestressedConcreteStructuresofMinistryofEducation,
SchoolofCivilEngineering,SoutheastUniversity,Nanjing,Jiangsu,P.R.China
bSchoolofEngineering,TheUniversityofBritishColumbia,Kelowna,BCV1V1V7,Canada
cKeyLaboratoryofConcreteandPrestressedConcreteStructuresofMinistryofEducation,
SchoolofCivilEngineering,SoutheastUniversity,Nanjing,Jiangsu,P.R.China
dSchoolofEngineering,TheUniversityofBritishColumbia,Kelowna,BCV1V1V7,Canada
Isolation bearings have been widely used to improve the seismic performance of highway
bridges. Considering the flexibility of the isolation systems, isolated highway bridges are
susceptible to unseating or even collapse due to excessive displacement under strong
earthquakes.Shapememoryalloy(SMA)wireswithsuperiorenergydissipationcapacityand
self-centering property can be utilized as seismic restrainers to limit the displacement.
However, there is no appropriate design method for SMA restrainers in isolated highway
bridges.TheobjectiveofthisstudyistoevaluatetheseismicperformanceofaLRBisolated
simply supported bridge retrofitted with SMA restrainers. A design procedure for SMA
restrainer is proposed according to a linearized two degree-of-freedom (DOF) analytical
model. The optimal design parameters, i.e. the ratio of the allowable displacement to seat
width(∆a/Lsw),normalizedelongationparameterofSMAcables(α),andhorizontalangle(θ0)
between the restrainer and horizontal level, are determined by conducting full factorial
analysis.Theresultsshowedthattheoptimalvaluesoftheratiooftheallowabledisplacement
toseatwidth(∆a/Lsw),whicheffectivelyreducestherelativedisplacementandsimultaneously
control the base shear of the piers, are between 0.4 and 0.7. The optimum value of the
horizontal angle (θ0) ranges from 0 to π/4. The optimum value of normalized elongation
parameter(α)shouldbe1.0.
Engineering Mechanics Institute
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131
A0313-Featuresofoffshoreseismicgroundmotionsdistinctfromtheonshore
Q.Zhanga,XiangYuanZhengb
aPhDcandidate,DepartmentofCivilEngineering,TsinghuaUniversity,
bProfessor,DivisionofOceanScienceandTechnology,TsinghuaUniversity,Shenzhen
GraduateSchool,[email protected]
Thefeaturesofoffshoregroundmotionshavenotyetbeenuncoveredthoroughlyforlacking
seafloor measured data. This study managed to collect more than 1000 offshore and
concurrentonshoresiterecordsfromtheK-NETandSEMSprojects.Thesedataarecompared
statisticallyintermsofthepeakgroundacceleration(PGA),thenormalizedresponsespectra
ofthehorizontalandverticalcomponentsandthecorrespondingvertical-to-horizontal(V/H)
ratios.Theanalysisindicatesthatinthesameearthquakeeventandwithidenticalepicenter
distance,duetotheeffectsofseafloorsoftsedimentsandwaterlayer,theoffshorehorizontal
PGAissignificantlyamplified.Meanwhile,thePGA’sV/Hratiooftheoffshoregroundmotions
is much smaller than that of the onshore counterparts. For response spectra, the peak
platforms of offshore ground motions lag behind the onshore records. Also, the offshore
responsespectraatlongperiodsgaingreateramplifications,whichiscriticaltobottomfixed
offshore structures. The V/H ratios of response spectra, offshore versus onshore, exhibit
differenttrendsvaryingwithperiods.Finally,tofillupthegapofcurrentseismicdesignof
offshorestructures,astandardizedresponsespectrumissuggestedforthereferenceusein
designcodes.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
132
A0355-Collapseperformanceassessmentofself-centeringprecastconcretewalls
withdifferentpost-tensioningandenergydissipationdesigns
HaoWua,YingZhoub
aAssistantresearcher,TongjiUniversity,[email protected]
dProfessor,TongjiUniversity,[email protected]
Previousresearchhaveprovedtheexcellentperformanceofself-centeringprecastconcrete
walls for use in seismic regions in terms of low damage and small residual deformation.
However, these studies have mainly focused on evaluating the hysteretic behavior of the
system through experimental testing and numerical simulation. This paper evaluates the
influences of different designs of post-tensioning (PT) and energy dissipation (ED)
components, which could be controlled by designers, on the collapse performance of self-
centeringprecastconcretewalls.Theeffectsofdifferentdesignselectionsfortheresponse
reductionfactor(R)andcollapsecriterionarealsoexamined.Tothisend,anexamplefour-
story self-centering precast wall building is designed and simulated using the numerical
modelthathasbeenverifiedbasedonexistedtestdata.Atotalofeightdifferentdesignsare
consideredfortheexamplebuildingusingvariousamountofPTandEDdesigns,anddifferent
Rvalues.Theestablishedparametricmodelsareanalyzedtoproducecollapsefragilitycurves
throughincrementaldynamicanalysisusing44groundmotions.Basedonresultsofcollapse
fragilitydata,collapseriskofalltheparametricmodelsareassessedaccordingtothestandard
procedureinFEMAP695.TheevaluationresultsshowthatEDdesignshavemoreinfluence
thanPTdesignstotheoverallcollapsefragilityforself-centeringprecastwalls.Nevertheless,
all the prototype walls in the current study are demonstrated to have acceptably low
probabilitiesofcollapse,whichmeettherequirementsinthedesigncode.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
133
A0523-Dynamictestingofafull-scalefrp-retrofittedreinforcedconcretebuilding
frame
JiukShina,Jong-SuJeonb
aResearchSpecialist,KoreaInstituteofCivilandBuildingTechnology,[email protected]
bAssistantProfessor,AndongNationalUniversity,[email protected]
Manyexistingreinforcedconcretebuildingsdesignedinaccordancewithpre-1971codesare
generally dominated by weak column-strong beam behavior under seismic loading due to
inadequatereinforcementdetailing.Thisbehaviorcanleadtoprematurefailureunderseismic
loadsfromdamageconcentratedinthefirststoryofthestructure.Thispaperpresentsfull-
scale dynamic testing of a non-ductile reinforced concrete frame retrofitted using a fiber-
reinforced polymer jacketing system on the first story columns. This retrofit scheme was
determinedbasedonvisibledamagepatternsandlocations(e.g.flexural,shearandlap-splice
failureonthefirststorycolumns)ofanas-builttestframe.Thefull-scaledynamictestwas
performed to investigate the dynamic performance of the retrofitted building structure in
terms of the modal response, inter-story drift, and effectiveness of the fiber-reinforced
polymerjacketingsystem.Theresultsdemonstratethattheretrofitschemehelpeddevelopa
moreuniformstorydriftdistribution,workingtocounterthesoft-storymechanismcommonly
foundinreinforcedconcreteframesdesignedduringthisperiod.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
134
A0530- Simplified model based on spectrum analysis for the optimal outrigger
locationofhigh-risebuildings
YingZhoua,LiliXingb,GuangxinZhouc
aStateKeyLaboratoryofDisasterReductioninCivilEngineering,TongjiUniversity,Shanghai
200092,China,[email protected]
bStateKeyLaboratoryofDisasterReductioninCivilEngineering,TongjiUniversity,Shanghai
200092,China,[email protected]
cStateKeyLaboratoryofDisasterReductioninCivilEngineering,TongjiUniversity,Shanghai
200092,China,[email protected]
The outrigger system is a current alternative to reduce the dynamic response of high-rise
buildings.Theaimofthestudyistodevelopanalyticalmethodsforearthquakeresponseofa
conventionaloutriggersystemandtodeterminetheoptimaloutriggerlocation.Atheoretical
simplifiedmodelisdevelopedbasedonadynamictime-historyloadandisfurtherimproved
bymode-superpositionresponsespectrummethod.ThemodelisthencalibratedviaanANSYS
model, and the simplified model is applied to perform parametric analyses to acquire the
optimal outrigger location of each scheme. All data obtained from parametric analyses are
summarisedtosolvethefittingequationofoptimaloutriggerlocation.Finally,acomparison
of the results between time-history and spectra analysis suggest that the simplified model
basedonspectrumanalysiseffectivelysimulatestheseismicbehaviourofstructurewithan
outriggeranditscorrespondingfittingequationreasonablyexpressestheoptimaloutrigger
location of the aforementioned type of structure under seismic action. Additionally, the
optimal outrigger location is first proposed in the form of an explicit equation that is
convenientlyusedintheinitialdesignprocessofaconventionaloutrigger.
Engineering Mechanics Institute
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135
A0567-Modelingandperformanceassessmentofbase-isolatedbuildings
N.D.Olivetoa,A.Athanasioub,A.A.Markouc
aVisitingscholar,UniversityofCatania,[email protected]
bPostdoctoralresearcher,ConcordiaUniversity,[email protected]
cLecturer,AaltoUniversity,[email protected]
The behavior of high damping rubber bearings is highly complex. Existing models are
generally unidirectional and for the most part difficult to extend to general bidirectional
loading. One of the major limitations is their inability to characterize the behavior of the
bearingsatdifferentlevelsofsheardeformation.Inthepresentwork,asetofbidirectional
modelsareproposedandimplemented,obtainedbysimplecombinationsofwell-knownbi-
dimensionalformulations.Themodelsareshowntoaccuratelydescribetheresponseofthe
bearingsatlow,intermediateandhighstrainlevelsusingasinglesetofparameters.Numerical
simulations are carried out of a base-isolated building subjected bidirectional earthquake
excitation. An ensemble of earthquake records are selected based on site hazard
characteristicsandusedforaperformancebasedassessmentofthebuilding.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
136
A0599-Verticalvibrationofend-bearingpilegroupsinviscoelasticsoillayer
LubaoLuana,XuanmingDingb,ChangjieZhengc
aPh.D,KeyLaboratoryofNewTechnologyforConstructionofCitiesinMountainArea,School
ofCivilEngineering,[email protected]
bProfessor,KeyLaboratoryofNewTechnologyforConstructionofCitiesinMountainArea,
SchoolofCivilEngineering,[email protected]
cLecturer,KeyLaboratoryofNewTechnologyforConstructionofCitiesinMountainArea,
SchoolofCivilEngineering,[email protected]
Ananalyticalsolutionisproposedforcalculatingthesteady-stateimpedancefactorsofpile
groupswitharbitrarypilememberssubjectedtoharmonicverticalloads.Anewinteraction
factorbetweentwopilesareintroducedbydefinitiononthebasisofsoilresistanceinsteadof
piledisplacements,toconsidertheeffectofpilegeometryonpile-soil-pileinteraction.Stress
distributionof thesoilaroundtheverticallyvibratingpile is firstdeterminedtodefinethe
interactionfactor.Accordingly,impedancefactorsofthepilegrouparederivedusingthenew
defined interaction factor and the popular principle of superposition. Finally, numerical
resultsareobtainedfortypicalparameterstoinvestigatethepilegeometryeffectsandoffer
insightintothemechanismofloadtransferbetweenpilesandtheirsurroundingsoils.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
137
A0614-Balancedesignbasedonthehorizontalandverticalcollapsemarginratios
ofsteelframestructures
ZhengHea,JeriniainaSitrakaTantelyb
aPh.D.,Dept.ofCivilEngineering,DalianUniversityofTechnology,[email protected]
dPh.D.candidate,Dept.ofCivilEngineering,DalianUniversityofTechnology,
Thecollapsesofsteelframestructuresunderstrongearthquakeshaveraisedmanyquestions
regardingtheadequacyofthecurrentseismicprovisionstopreventapartialortotalcollapse.
Theyhavealsobroughtupquestionsastowhatarethetypicalcollapsemechanismsforthe
buildingstructures,what istheinherentsafetymarginincode-designedstructuresinboth
lateralandverticaldirections,howtostrengthenthestructurestoeffectivelyincreasesuch
margins,andhowtobalancethesemarginstooptimizetheoverallsafetyofthestructures.
Thispaperpresentsamethodologytoimprovetheglobalcollapseresistanceofthestructures
bybalancingthecollapsemarginratio(CMR)inbothlateralandverticaldirections.Basedon
theconceptofsafetybalancedesign,thecharacteristicsofunbalanceddesignareidentifiedto
develop a series of steel frame structures with typical failure mechanisms. The safety
assessmentofeachexamplestructure,intermofhorizontalandverticalCMR,isperformed.
TheoutcomespermittodeveloptheenvelopeofCMR,whichreflectstherelationshipbetween
thetwoCMRs.Thesuperpositionoftheparametersofthestructuralcollapsesensitivitytothe
envelope of CMR allows identifying the critical CMR values in both lateral and vertical
directions.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
138
A0673-Seismicvulnerabilityofrailwaynetworkbasedontherunning-trainssafety
evaluation
ChengYANGa
aAssociateProfessor,[email protected]
The medium-small earthquakes could induce the high-speed train derailment on bridges
withoutanybridgestructuraldamage,leadingtotherailwaylinesblockage.Fordepictingthe
seismic hazard scenario of high-speed railway network, a framework is proposed to
investigate the connectivity vulnerability of China high speed-railway network under the
effect of regional earthquake. Based on a dense bridges network covering an earthquake-
proneareaofsouthwestChina,thePSHAisperformedtogettheseismichazardparameters
ofeverybridgesite.Asaresult,theaccelerationresponsespectrumcorrespondingtodifferent
earthquake recurrence interval is obtained. After vehicle-bridge-earthquake dynamic
analyzing, the seismic induced derailment probability of vehicles moving on the bridge is
obtainedandtakenastheclosingprobabilityofthenodesinthenetwork.Basedonthenode
closing probability corresponding to different levels of earthquake, the Order-X network
connectivityalgorithmispresentedtocalculatethenetworkconnectivity.Theresultsshow
thatthedifferencebetweenthemicro-zoningintensityandmacro-levelintensity,whichleads
to the difference in hazard assessment results for bridges, is the key factor that cause the
difficultiesofconnectivityvulnerabilityanalysis,hence,thesafetyevaluationofrunning-trains
onbridgesisindispensablefortheseismicvulnerabilityanalysisofthebridgesnetwork.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
139
A0754-Seismicresponseanalysisofliquidpipesinbuilding
HaoRunxiaa,YuanPengchengb
aAssociateprofessor,CivilEngineeningSchool,InnerMongoliaUniversityofScience&
Technology,[email protected]
dPostgraduatestudent,CivilEngineeningSchool,InnerMongoliaUniversityofScience&
Technology,[email protected]
Theliquidpipesinthebuildingareusedasnon-structuralmembersattachedtoeachfloor,
which is of great significance for ensuring the normal use of the building. Based on the
influenceofeachfloorofthemainstructureonthepipeline,establishesthemainstructure-
pipe integral coupling model and the pipeline multi-point excitation model to analyze the
seismicresponseofthepipeline,andcomparestheresultsofthetwotoproposeamulti-point
excitationpipelineseismicresponseanalysismethod.Throughthetime-historyanalysisofthe
7-story frame structure, the influence law of ground motion intensity variation on the
accelerationamplificationcoefficientofeachfloorisobtained.,andtheseismicresponseof
thefloorresponsespectrumanalysispipelineisestablished.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
140
A0851-Multiscalerandomfields-baseddamagemodelingandanalysisofconcrete
structures
HaoZhoua,JieLib,BillieF.SpencerJr.c
aPhD,DepartmentofCivilEngineering,SouthChinaUniversityofTechnology,381Wushan
Road,Guangzhou,China,[email protected]
bProfessor,DepartmentofStructuralEngineering,TongjiUniversity,1239SipingRoad,
Shanghai,China,[email protected]
cProfessor,DepartmentofCivilandEnvironmentalEngineering,UniversityofIllinoisat
Urbana-Champaign,IL61801,[email protected]
Anewapproachtowardsincorporatingthestochasticnatureofdamageconstitutiverelations
ispresentedforthefiniteelementanalysisofconcretestructures.Withintheframeworkof
stochastic damage mechanics, the spatial variability of concrete is modeled as a two-scale
stationaryrandomfields.Atthemicro-level,thedamageevolutionlawofconcreteismapped
to a random field corresponding to the microscopic fracture strain. At the macro-level, the
strengthdistributionofconcretecomponentsformsalognormallydistributedrandomfield.
Thecovarianceconstraintisdevelopedtobridgethegapbetweenthetwo-scalerandomfields
suchthatthescale-of-fluctuationoftherandommaterialpropertyissatisfiedinbothscales.
Taking advantage of the stochastic finite element method, both the microscopic random
damageevolutionofconcreteandthefluctuationofmacroscopicstructuralresponsescanbe
numerically represented. Stochastic structural modeling and damage analysis regarding a
high-risereinforcedconcretestructureiscarriedouttoillustratetheproposedmethod.Itis
shownthatthenonlinearbehaviorofthestructuresubjectedtostrongdynamicactionsmay
exhibitsignificantvariabilityandevenitsintendedcollapsemodesmaybealteredmerelydue
torandomnessinmicroscaleofconcrete.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
141
A0883-Dynamictestingofafull-scalefrp-retrofittedreinforcedconcretebuilding
frame
JiukShina,Jong-SuJeonb
aResearchSpecialist,KoreaInstituteofCivilandBuildingTechnology,[email protected]
dAssistantProfessor,AndongNationalUniversity,[email protected]
Manyexistingreinforcedconcretebuildingsdesignedinaccordancewithpre-1971codesare
generally dominated by weak column-strong beam behavior under seismic loading due to
inadequatereinforcementdetailing.Thisbehaviorcanleadtoprematurefailureunderseismic
loadsfromdamageconcentratedinthefirststoryofthestructure.Thispaperpresentsfull-
scale dynamic testing of a non-ductile reinforced concrete frame retrofitted using a fiber-
reinforced polymer jacketing system on the first story columns. This retrofit scheme was
determinedbasedonvisibledamagepatternsandlocations(e.g.flexural,shearandlap-splice
failureonthefirststorycolumns)ofanas-builttestframe.Thefull-scaledynamictestwas
performed to investigate the dynamic performance of the retrofitted building structure in
terms of the modal response, inter-story drift, and effectiveness of the fiber-reinforced
polymerjacketingsystem.Theresultsdemonstratethattheretrofitschemehelpeddevelopa
moreuniformstorydriftdistribution,workingtocounterthesoft-storymechanismcommonly
foundinreinforcedconcreteframesdesignedduringthisperiod.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
142
A0899- Multi-scale comprehensive simulation of concrete shear wall models:
numericalsimulation
JingranHea,JianbingChenb,XiaodanRenc,JieLid
aPh.D.candidate,TongjiUniversity,Shanghai,China,[email protected]
bProfessor,TongjiUniversity,Shanghai,China,[email protected]
cAssociateProfessor,TongjiUniversity,Shanghai,China,[email protected]
dDistinguishedProfessor,TongjiUniversity,Shanghai,China,[email protected]
Concretestructuresarewidelyusedintheworld,particularlyinChina,wheremostareasare
earthquake prone zone, therefore their safety is of great importance. The prediction and
simulation of such structures under strong earthquakes are essential to the performance
evaluationandreliabilityassessment.However,duetotheuncertaintiesinmaterialproperties
and numerical modelling, the accurate simulation of complex concrete structures is still a
greatchallenge.Thelackofknowledgeintheconstitutivelawofconcrete,forinstance,isone
of the uncertainties that is most essential to the simulation. In recent years, a stochastic
damagemodelforconcretematerialhasbeendeveloped.Thismesoscopicphysicalmodelcan
capturethemechanicalbehaviorofconcrete.Inthepresentpaper,thepredictionofresponse
ofastructuralmodelinshaketabletestsisconductedbydifferentconstitutivelaws,including
theconcretedamageplasticmodel(CDP)which isembeddedintheABAQUSsoftware, the
stochastic damage model (SDM) and the stochastic damage model with softening effect
(SDMs).Thesimulationresultsoftheseconstitutivelawsarecomparedwiththetestresults,
showingthattheSDMandSDMsperformancebetterthantheCDP.Theresultdemonstrates
thattoadoptappropriateconstitutivelawofconcrete,includingtheinvolvementofcompound
effects of concrete and reinforcement, is essential to the simulation of strong nonlinear
behaviorsofconcretestructures.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
143
MS13: Damage and Failure Modeling and Analysis of
Concrete and Structures
A0119-AfractureproblemwithasurfaceenergyintheSteigmann-Ogdenform
AnnaZemlyanovaa
aAssociateProfessor,DepartmentofMathematics,KansasStateUniversity,Manhattan,KS,
USA,e-mail:[email protected]
A problem of a straight mixed mode non-interface fracture in an infinite plane is treated
analytically with the help of complex analysis techniques. The surfaces of the fracture are
subjectedtosurfaceelasticityintheformproposedbySteigmannandOgden.Theboundary
conditions on the banks of the fracture connect the stresses and the derivatives of the
displacements.Themechanicalproblemisreducedtoasystemofsingularintegro-differential
equationswhichisfurtherreducedtothesystemsofequationswithlogarithmicsingularities.
ItisshownthatmodelingofthefracturewiththeSteigmann-Ogdenelasticityproducesthe
stressandstrainfieldswhichareboundedatthecracktips.Theexistenceanduniquenessof
thesolutionforalmostallthevaluesoftheparametersisprovedbyreducingthesystemof
singularintegro-differentialequationstothesystemofweakly-singularintegralequations.It
isshownthatintroductionofthesurfacemechanicsintothemodelingoffractureleadstothe
size-dependent equations. A numerical scheme of the solution of the systems of singular
integro-differential equations is suggested, and the numerical results are presented for
differentvaluesofthemechanicalandthegeometricparameters.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0124- MULTILEVEL MODELING OF FIBER-REINFORCED CONCRETE AND
SIMULATIONOFCRACKINGINTUNNELLININGSEGMENTS
Y.ZhanaandG.Meschkeb
aSeniorR&DEngineer,ShanghaiConstructionGroupCo.,Ltd.,Shanghai200080,China,
email:[email protected]
bProfessor,InstituteforStructuralMechanics,RuhrUniversityBochum,Bochum44801,
Germany,email:[email protected]
Aimingatthemodel-basedanalysis,designandoptimizationofengineeringstructuressuch
assegmentaltunnel liningsmadeof fiber-reinforcedconcrete(FRC),amultilevelmodeling
framework consisting of a series of model components is developed, which facilitates the
investigationoftheeffectofvariousdesignparameters(concreteclass,fiberproperty,fiber
distribution,etc.)atdifferentlengthscales.Thefundamentalingredientatthelevelofsingle
fibersisananalyticalmodelallowingthepredictionofthepulloutresponseofasteelfiber,
eitherstraightorwithhookedend,withorwithout inclinationwithrespect to the loading
direction.ForanopeningcrackinaspecificFRCcomposite,employingthesinglefiberpullout
model,thefiberbridgingeffectiscomputedviatheintegrationofthepulloutresponsesofall
the fibers intercepting the crack, taking particularly the anisotropic fiber orientation into
consideration. Based on the numerically integrated results of crack bridging effect, the
corresponding analytical surrogate function form of the traction–separation relation is
derived. For the numerical analysis of fracture processes and failure mechanisms at the
structurallevel,thefiniteelementmethodusinginterfacesolidelementsequippedwiththe
traction–separation law obtained from the crack bridging model is used to capture the
cracking phenomena and the postcracking ductile behavior of FRC. An implicit/explicit
integrationschemeandanadaptivemesh-processingtechniqueareimplementedtoenhance
therobustnessandtoreducetheexpenseofcomputation.Havingthesemodelcomponents
validated,thecompletemultilevelmodelingframeworkisappliedtothesimulationoffailure
behavior of tunnel lining segments made of FRC, demonstrating good performance in
followingtheinfluenceofdifferentdesignparametersfromthesinglefiberleveltothescale
ofengineeringstructures.Therefore,thepresentworkconstitutestheessentialingredientsof
a“virtuallaboratory”forthedesignandoptimizationofFRCmaterialsandstructures.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0274-NUMERICALINVESTIGATIONOFCONCRETEAGEEFFECTONSHEARLOAD
CAPACITYOFPOST-INSTALLEDANCHORS
KrešimirNinčevića*,IoannisBoumakisaandRomanWan-Wendnera
aChristianDopplerLaboratoryforLife-CycleRobustnessinFasteningTechnologyUniversity
ofNaturalResourcesandLifeSciencesVienna,Austria.*CorrespondingAuthore-mail:
Fasteningsystemsarewidelyusedengineeringsolutionssupportinginnovativedemandsin
design. Fasteners are used to connect structural members or attach secondary elements.
Additionally, they see many others applications such as strengthening existing structures/
structuralmembers.Thepresentinvestigationfocusesontheshearloadcapacityofanchors
installedinconcreteclosetoanexistingedge.Thedominantfailuremechanisminthiscaseis
concreteconebreakout.Thisfailuremechanismhasbeeninvestigatedformanyyears,andas
aresult,differentanalyticalmodelshavebeenderivedasafunctionofembedmentdepthand
edgedistance,inthelattercasewithvaryingsuccess.Thesemodelsseemtobevalidsolutions
fordesigningsafeandreliablefasteningsystems.Nevertheless,noneofthemconsidersthe
complexagingnatureoftheheterogeneousmaterialconcrete.Indesignconcreteisconsidered
ahomogenousmaterialwithspatiallyconstantmaterialproperties.However, inreality the
mechanicalpropertiesarefunctionsofthelocalcementhydrationdegree,ratherthantime,
which not only depend on the mix design but also on the history of the environmental
boundary conditions (i.e. temperature and relative humidity). Consequently, the concrete
volume involved in the forming concrete breakout body is characterized by gradients of
materialproperties(andpotentiallyalsoshrinkagestrains)thatdonotscalewiththeedge
distance.Furthermore,aso-calledwall-effectisknowntoexist,i.e.theconcreteclosetothe
surface differs in composition and material properties from the bulk. This contribution
presents a large experimental campaign comprising shear tests on post-installed bonded
anchors for three concretes, two ages and three edge distances each. Tests include a full
fracturemechanicalcharacterizationatbothages,calorimetry,creep,andshrinkagetests.A
discretemulti-physicsframeworkisappliedinordertoinvestigatetheinfluenceoftheedge
distanceontheconcreteshearcapacityexplicitlyaccountingfor(i)thewall-effect,(ii)curing
relatedgradientsinmaterialpropertiesand,thus,aging,and(iii)thedistributionofshrinkage
strainsandearlyagedamage.TheLatticeDiscreteParticleModel(LDPM)isusedtosimulate
concrete at the meso-scale and to mimic its heterogeneity while the degree of curing is
determinedbythehygro-thermalchemical(HTC)model.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0378-Analyticalmodelofrockingelementswithdamagedcorners
HaoranCuia,DechengFengb,GangWuc,*
aPh.D.candidate,SchoolofCivilEngineering,SoutheastUniversity,e-mail:
bLecturer,SchoolofCivilEngineering,SoutheastUniversity,e-mail:[email protected]
cProfessor,KeyLaboratoryofConcreteandPrestressedConcreteStructuresoftheMinistry
ofEducation,SoutheastUniversity,e-mail:[email protected]
Therestraintsatthejointsofrockingstructuresarereleasedsothatrockingmotionscanoccur
during earthquakes. Damage to the main structure is limited by the concentrated
displacement at rocking interfaces, while corners of reinforced concrete rocking elements
crushduringtherockingmotion.Therockingelementexhibitsanonlinearbehaviordueto
the absence of tensile resistance in the end section in prerocking phase. A new analytical
modelwhichreferstoanexistinganalogousspreadplasticitymodelofrockingelementsis
developedtocalculatethedeformationofdamagedrockingelementsbeforerockingbasedon
virtueworkprinciple.Adamageinfluencecoefficient isproposedtoconsidertheeffectsof
damaged corners on the entire rocking elements, with a new effective stiffness ratio
accountingfortheplasticdeformationincalculation.Theanalyticalmodelisverifiedbythe
finiteelementmodelsimulationandtheresultsofexistingexperiments.Theresultsindicate
thattheanalyticalmodelproposedinthispapercouldaccuratelypredictthedeformationof
rockingelementsbeforeandafterdamage.Theeffectivestiffnessratiorelatedtothenormal
stressdistributionatthecontactsurfaceisprovedtobeapplicableintheanalysisofrocking
elementsbeforerocking.Byadjustingthedamageinfluencecoefficient,theeffectsofdifferent
damagedegreesofcornersonthestiffnessofrockingelementscanbeexplicated.Thedamage
influence coefficient increases as the range of damaged corners increase, which finally
decreasesthelateralstiffnessoftheentirerockingelement.
Engineering Mechanics Institute
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A0463- Simplified modal properties analysis of soil-base-isolated-structure
systemswithlargeaspectratio
D.S.Du,S.G.Wanga
aCollegeofCivilEngineering,NanjingUniversityofTechnology,Nanjing210009,China
Asimplifiedmethodologyisrigorouslystudiedinthispapertoanalyzeseismicresponseof
base-isolatedstructureswithdynamicsoil-structureinteraction(SSI)beingconsidered.The
proposedmethodologyisdevelopedbasedontheexistingsimplifiedmethodologywhichis
only applicable for non-isolated structures. The base-isolated structure model with two
degreesoffreedomissupportedbyswayingandrockingspringsandbythecorresponding
dashpots. Rigorous mathematical derivation is performed, and closed-form formulas of
natural periods, modes and modal damping ratios are derived. Furthermore, the overall
accuracy of the proposed methodology was checked against the results of the rigorously
derivedcomplexeigenvalueapproachproposedbyConstantinouandKneifati.Aparametric
studyisalsoconductedontheSSIeffectsofbase-isolatedstructures,whichturnsoutthattall
and slender structures with stiff isolation systems are more affected by SSI effects in
comparison to flexible superstructures. The proposed method provides a feasible way to
evaluateSSIeffectsofbase-isolatedstructuresefficientlyduringtheschematicdesignphase.
Engineering Mechanics Institute
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A0466- A NEW MODEL FOR DUCTILE FRACTURE PREDCTION WITH STRESS
TRIAXIALITYANDLODEDEPENDENCE:MODELLINGANDCALIBRATING
BoYanga,DeyangKongb
a,Professor,ChongqingUniversity,e-mail:[email protected]
b,Ph.D,ChongqingUniversity,e-mail:[email protected]
Fracture prediction is of great importance in structural steel in order to simulate the
progressivedamageandcollapseofsteelstructurebuildings.Whenfractureoccursincritical
components,suchasbeam-columnconnections,thestructuralperformanceincludingtheload
transfer paths and load-resistance mechanisms may be different, which may lead to an
overestimation of structural performances against progressive collapse, leaving a potential
threattohumanlives.However,previousstudiesonductilefractureofstructuralsteelsare
relatively limited. In this paper, a new ductile fracture model was developed based on
microstructural analysis of fracture process including void nucleation, growth and
coalescence.AseriesoffracturetestswerecarriedoutbyusingQ690Dsteeltocalibrateand
verifythenewlyproposedmodel.Thesetestsincludingtensiletestsofsmoothandnotched
roundbarspecimensandshearspecimenswereexpectedtofailatdifferentstresstriaxiality
regimes.Itisfoundthatthenumericalpredictionsagreewellwiththeexperimentalresults,
which demonstrates the new model can describe the ductile fracture behavior with high
accuracy.
Engineering Mechanics Institute
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A0504- Development and Identification of Hysteresis Model for Reinforced
ConcreteColumnsFailinginDifferentModes
XinliangLyua,XiaodanRenb,ChaolieNingc*
aMasterstudent,CollegeofCivilEngineering,TongjiUniversity,Shanghai200092,China,e-
mail:[email protected]
bAssociateProfessor,CollegeofCivilEngineering,TongjiUniversity,Shanghai200092,China,
e-mail:[email protected]
cAssistantProfessor,ShanghaiInstituteofDisasterPreventionandRelief,TongjiUniversity,
Shanghai200092,China,*CorrespondingAuthore-mail:[email protected]
Reinforced concrete (RC) columns have three different failure modes during earthquake
excitations,respectivelyflexural failuremode, flexural-shearfailuremodeandshear failure
mode, then exhibiting different hysteresis characteristics such as strength deterioration,
stiffnessdegradationandpinchingphenomenainapplications.Thus,thedevelopmentofan
effectiveandcomputationallyefficienthysteresismodeliscrucialfortheevaluationofseismic
performance of existing RC columns. However, the available hysteresis models are rather
complicated and the parameters involved in the hysteresis models often lack physical
interpretation, which largely prevents its flexible applications in practice. Therefore, a
simplifiedhysteresismodel is firstproposed in thisstudywithsevenmodelparametersto
describethedifferenthysteresisloopofRCcolumnsunderdifferentfailuremode.Then,the
differential evolution (DE) algorithm is employed to identify the value of hysteresis model
parametersbycomparingwiththeexperimentaldataof251RCcolumnsunderquasi-static
testing. Based on the identified value of hysteresis model parameters, a comprehensive
comparison of critical model parameters is finally made to provide a quantitative
understanding on the difference of the three different failure modes. According to the
investigation,itisfoundthatthehysteresismodeldevelopedwiththesevenmodelparameters
is adequate to capture the typical hysteresis characteristics of RC columns under different
failure mode. The DE algorithm is also effective to identify the value of hysteresis model
parameters.ForRCcolumnsfailinginflexural-shearmodeandshearmode,severerstrength
deterioration,stiffnessdegradationandpinchingphenomenacanbeobserved.Therefore,a
practical way should be further established to estimate the value of hysteresis mode
parameters based on the critical physical parameters of RC columns for facilitating its
applications.
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International Conference 2018 November 2-4 Tongji University
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A0604-Three-DimensionalFiniteElementModellingofUHPFRCJacket-Retrofitted
PiersUnderCyclicLoading
HaipengLeia,TengTongb,WeidingZhuoc,ZhaoLiud
aPhDcandidate,SoutheastUniversity,e-mail:[email protected]
bLecturer,SoutheastUniversity,e-mail:[email protected]
cPhDstudent,SoutheastUniversity,e-mail:[email protected]
dProfessor,SoutheastUniversity,e-mail:[email protected]
Inseismicevaluationofhighwaybridges,reinforcementconcrete(RC)piersarecriticaland
vulnerable components. There exists numerous old bridge piers with lower longitudinal
reinforcement ratio in China. Recently, the authors proposed a new retrofitted method by
usingultra-highperformancefiberreinforcedconcrete(UHPFRC)jacket.Cyclicloadingtest
showed that UHPFRC was a promising material significantly enhanced RC piers’ seismic-
resistantcapacity.Inthisstudy,the3Dsolidfiniteelementmodelisproposed,relyingonthe
implicitmethod,tonumericallyinvestigatetheeffectivenessofUHPFRCjacket.The3Dmodel
integratestheconcretedamageplasticity(CDP)modelfornormalconcreteandUHPFRC,the
constitutivemodelforreinforcementsincludinglocalbucklingandlow-cyclefatigue,andthe
strainpenetrationeffectbetweenconcreteandreinforcement.The3Dmodellingschemeis
implementedinthecommercialfiniteelementprogramABAQUS.Theconstitutivemodelfor
reinforcements is realized in UMAT routine, and the bond between concrete and
reinforcementismodelledthroughUELroutine.Thecomparisonwiththetestvalidatesthe
proposed3Dmodel.TheconfinementeffectfromUHPFRCjacket,isanalyzedindetailwiththe
numerical tool. The influencing factors of UHPFRC jacket on the effectiveness of seismic
retrofit,includingtheheightandthickness,areinvestigatedindetail.
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A0635-Spatialcorrelationindisorderedheterogeneousmaterials
DingZhaodonga
aSchoolofCivilEngineering,HefeiUniversityofTechnology,Hefei,China
The fracture patterns and damage localization of heterogeneous materials are strongly
influenced by the disorder at microscale. This paper investigates the spatial correlation of
strengthdistributionofbasicelementssystematicallywithrandomfusemodel(RFM).With
the same level of disorder, the spatial correlation determines different failure modes
characterized by transition from ductile failure to brittle failure. The statistical avalanches
scaling results also show not only the disorder but also the spatial correlation have great
influenceonmaterial failurecharacteristicswhich linkwith the firstorderandcontinuous
phasetransition.
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A0970-Anequivalentstrainbasedmulti-scaledamagemodelofconcrete
ShixueLianga,JinZhangb
aLecturer,SchoolofCivilEngineeringandArchitecture,ZhejiangSci-TechUniversity,e-mail:
bGraduateStudent,SchoolofCivilEngineeringandArchitecture,ZhejiangSci-Tech
University,e-mail:[email protected]
Amulti-scaledamagemodelofconcreteisproposedbasedontheconceptofenergyequivalent
strain for generic two- or three-dimensional applications. Continuum damage mechanics
servesastheframeworktodescribethebasicdamagevariables,namelythetensileandshear
damage.ThehomogenizedHelmholtzfreeenergyisintroducedasthebridgetolinkthemicro-
cell and macroscopic material. The crack propagations in micro-structures subjected to
tensionandsheararemodeled,andtheHelmholtzfreeenergyinthecrackedmicro-structure
is calculated and employed to extract the damage evolution functions in the homogenized
continuum. Based on the damage energy release rates (DERRs) and damage consistent
condition,theenergyequivalentstrainisusedtoexpandtheuniaxialdamageevolutiontothe
multi-axialdamageevolution.Agreementswithexistingexperimentaldatathat includethe
uniaxialtensileandcompressivetests,thebiaxialcompressionprovethecapacityofthemulti-
scaledamagemodelinreproducingthetypicalnonlinearperformancesofconcretespecimens.
Thesimulationofreinforcedconcreteundergrounddiaphragmwallfurtherdemonstratesits
applicationtoconcretestructures.
Engineering Mechanics Institute
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MS14: Uncertainty Quantification and Reliability-based
Performance Evaluation
A0020- ROBUST STATISTICAL METHODS FOR POWER SPECTRUM ESTIMATION
FROMMULTIPLESOURCERECORDS
MarcoBehrendta,LiamComerfordb,MichaelBeerc
aM.Sc.,InstituteforRiskandReliability,LeibnizUniversityHanover,e-mail:
bDr.,InstituteforRiskandReliability,LeibnizUniversityHanover,e-mail:
cProf.Dr.-Ing.,InstituteforRiskandReliability,LeibnizUniversityHanover,e-mail:
Modernapproachestosolvedynamicproblemswhererandomvibrationisofsignificancewill
inmostofcasesrelyuponthefundamentalconceptofthepowerspectrumasacoremodelfor
excitation&responseprocessrepresentation.Thisispartlyduetothepracticalityofspectral
modelsforfrequencydomainanalysis,aswellastheireaseofuseforgeneratingcompatible
timedomainsamples.Suchsamplesmaybeutilizedfornumericalperformanceevaluationof
structures,thoserepresentedbycomplexnon-linearmodels.Utilizationofensemblestatistics
willbeconsideredfirstforstationaryprocessesonly.Forastationarystochasticprocess,its
powerspectrumcanbeestimatedstatisticallyacrossalltimeorforasinglewindowintime
acrossanensembleofrecords.Inthiswork,itisshownfirstthatensemblecharacteristicscan
beutilizedtoimprovetheresultingpowerspectrabyusingestimationsofthemedianinstead
ofthemeanofmultipledatarecords.Theimprovedpowerspectrumwillbemorerobustin
thepresenceofspectraloutliers.Themedianspectrumwillresultinmorereliableresponse
statistics, particularly when source ensemble records contain low power spectra that are
significantly below the mean. As an extension, a weighted median spectrum will also be
utilized,baseduponthespectraldistanceofeachrecordfromthemedian,whichwillshiftthe
estimatedspectruminthedirectionoftheclosestsamples.Tovalidatetheimprovedmethod
ofestimatingpowerspectrawindandearthquakeloadsareappliedtohigh-risebuildings.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0131-ANALYZINGCOMPLEXSYSTEMSUNDEREPISTEMICUNCERTAINTIES
MichaelBeer
InstituteforRiskandReliability,LeibnizUniversitätHannover,Germany,e-mail:
InstituteforRiskandUncertainty,UniversityofLiverpool,UK
InternationalJointResearchCenterforEngineeringReliabilityandStochasticMechanics
(ERSM),TongjiUniversity,China
Our structures, systems and infrastructure are characterized by a rapid growth in scale,
complexityandinterconnectionwithasignificantinvolvementofdiversehumanbehaviour
withcriticalinfluence,sothatuncertaintiesandrisksareinvolvedtoagreaterextentthanever
before.Thesestructures,systemsandinfrastructureare,toasignificantextent,criticalforthe
functionality of our economic and societal life, and thus, require proper approaches and
measures to verify and ensure their reliable performance. Reliability and performance
analysis,however,becomeincreasinglycomplicatedduetouncertaintiesandcomplexity.The
realisticquantificationofuncertaintiesandtheirnumericallyefficientprocessingincomplex
analysesarethetwokeychallengesinthiscontext.Thiskeynotelectureaddressesthesetwo
challenges. Approaches to deal with epistemic uncertainties are discussed, with focus on
impreciseprobabilitiesandinthecontextofstructuralandsystemreliabilityassessment.The
concept of survival signature is presented to analyse complex systems efficiently. Novel
pathways to capture interdependencies between systems while estimating their reliability
efficientlyinatimedependentmannerarediscussed.Engineeringexamplesarepresentedto
demonstratethecapabilitiesoftheapproachesandconcepts.
Engineering Mechanics Institute
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A0179- EFFICIENT BRIDGE LIFETIME ASSESSMENT BY TRAFFIC LOAD MODEL
UPDATINGANDSUBSETSIMULATION
StephenWua,He-QingMub*,Hou-ZuoGuoc
aAssistantProfessor,TheInstituteofStatisticalMathematics,Tokyo190-8562,Japan.E-mail:
b*AssociateProfessor,SchoolofCivilEngineeringandTransportation,StateKeyLaboratory
ofSubtropicalBuildingScience,SouthChinaUniversityofTechnology,Guangzhou510640,
P.R.China.CorrespondingAuthorE-mail:[email protected]
cStudent,SchoolofCivilEngineeringandTransportation,SouthChinaUniversityof
Technology,Guangzhou510640,P.R.China.
Wedemonstrateaproof-of-conceptstudyonefficientbridgelifetimeassessmentusinglimited
amount of traffic load data. Conventional approach fits a standard distribution, such as a
normaldistribution,withobservedtrafficloadinagivenperiod.Then,thedistributionisused
to predict future traffic load, leading to the final lifetime assessment of a bridge. As the
reliability estimation of a bridge depends heavily on the rare traffic load effect events, the
conventionalapproachisinefficientandinaccurateforpracticalpurposes.Weproposeamore
effectiveuseofthetrafficloaddatausingabetterbridgereliabilityassessmentframework.
Ourframeworkinvolvesareal-timeupdatingloopcomposedoftwocomputationalmodules:
(1) a traffic load simulation model continuously trained by real data, and (2) a machine
learningmodel forbridgeresponsepredictiontrainedbytheupdatedtraffic loadmodel.A
reliablesimulationmodelcanguaranteethesupplyofsufficientdataforaccuratereliability
assessment,andamachinelearningmodelcanspeedupthereliabilityestimationprocess.To
further improve the efficiency of our algorithm, we employ the popular subset simulation
method toestimateextremely small failureprobability values.Theproposed framework is
validatedbysimulatedexamples.
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International Conference 2018 November 2-4 Tongji University
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A0203-StochasticStayCableForceModelingUsingMonitoringDatafromaCable-
stayedBridge
HaijunZhoua,JunhuiLiub,QiWenc,LiminSund
aPhD,Professor,GuangdongProvincialKeyLaboratoryofDurabilityforMarineCivil
Engineering,ShenzhenUniversity,e-mail:[email protected]
bResearchAssistant,GuangdongProvincialKeyLaboratoryofDurabilityforMarineCivil
Engineering,ShenzhenUniversity,e-mail:[email protected]
cResearchAssistant,GuangdongProvincialKeyLaboratoryofDurabilityforMarineCivil
Engineering,ShenzhenUniversity,e-mail:[email protected]
dPhD,Professor,StateKeyLaboratoryforDisasterReductioninCivilEngineering,Tongji
University,Shanghai200092,CHINA,e-mail:[email protected]
The monitoring data of cable force, cable temperature from a cable-stayed bridge were
analyzed.Thedailyaveragevaluesofcableforceandcabletemperatureareusedtoeliminate
the variation effects of one day’s temperature. Then the data of cable force and cable
temperature were linear regression analyzed. The results showed that the coefficient of
determinationwasabout0.3andtheresiduewassymmetricallyaroundtheregressionline.
TheresiduecableforcevariationalonetimewasthenmodeledaspotentiallyGaussianand
homogeneous stochastic fields. Autocorrelation functions and marginal probability
distributionfunctionsweredeterminedfortheresidualradiusstochasticfield.Itwasfound
that the residual value of cable force was stationary and the marginal distribution did not
rejectnormaldistribution.Thestochasticmodelofcableforcethateliminatingtheeffectsof
cabletemperaturewasestablishedbasedonabovestudies.
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A0222- Multi Level Moving Particles Simulation for Reliability Assessment with
ApproximateLimiteStateFunctions
C.Proppea
aChairofEngineeringMechanics,KarlsruheInstituteofTechnology,Kaiserstr.10,Bdg.10.23,
76131Germany,e-mail:[email protected]
MarkovChainMonteCarlosimulationmethodsallowestimatingsmall failureprobabilities
efficiently,evenforproblemsthatinvolveahigh-dimensionalvectorofinputrandomvariables.
Subsetsimulationcanbeconsideredasthemostprominentmethodinthisclass.Insubset
simulation, the failure probability is computed as the telescoping product of larger
probabilitiesthatrequiresamplingfromconditionaldistributions.Recently,analternativeto
subsetsimulationinthesenseofparticlemethodshasbeenproposed,whereathresholdis
associatedtoeachsample,samplesaremovedtonewpositionsinthedesignspaceandthe
numberofmovesfortheinitialsamplestoreachthefailureregionarecountedandyieldan
estimator for the failureprobability,which isofcomparableaccuracyandefficiencyas the
subsetsimulationestimator.Thealgorithmallowsforaneasyparallelimplementation.Justas
for subset simulation, sampling from conditional distributions is required when moving a
particle.Inmostpracticalapplications,thelimitstatefunctionisapproximatednumerically
with a certain numerical error h. In order to obtain an efficient simulation algorithm, it is
necessarytobalancethestatisticalerrorandthenumericalerror.Inthispresentation,amulti
levelmovingparticlessimulationmethodisproposedthatbalancesbotherrorsbycomputing
atelescopingsumofestimatesforthenumberofmoves.Foreachterminthetelescopingsum,
itisnecessarytocomputeascorrectorthedifferenceofthenumberofmovesforeachinitial
samplewithtwoconsecutiveaccuracylevelsusingthesamerandomnumbersintheMarkov
Chain Monte Carlo simulation. For the multi level moving particles method, the sample
variancedecreaseswithdecreasingnumericalerror.Thus,thenumberofsamplesthathasto
beevaluatedwithhighaccuracyisreducedcomparedtoasinglelevelcomputation.Therefore,
theproposedalgorithmisveryefficientforproblemswherehighlyaccurateevaluationsofthe
limitstatefunctionarenecessaryandrequireahugecomputationaleffort.
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International Conference 2018 November 2-4 Tongji University
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A0389-PrestressedConcreteBeamsFailingduetoWeb-crushing:Uncertaintyand
Reliabilityanalysis
OladimejiBenedictOlalusia
aStellenboschUniversity,SouthAfrica,e-mail:[email protected]
Shearfailureinprestressedconcretebeamswithstirrupreinforcementsandrelativelythin
websmaybegovernedbyweb-crushingfailure.Inthisscenario,theconcretediagonalswould
crushbeforetheyieldingoftheshearreinforcement,resulting inabrittlefailuremode.An
accurate method for predicting web-crushing failure is paramount since web-crushing is
catastrophicandcouldoccurwithoutwarning(brittlefailure).Theaccuratepredictionofthe
web-crushingstrengthofbeamsisaninvolvedprocess.Consequently,manycodesofpractices
have resorted to implementing simplified methods for predicting web-crushing failure in
beams.Therefore,itseemedreasonabletoassesshowwellthedesignprocedurescanpredict
theweb-crushingstrengthinprestressedconcretebeams.Thepaperaimstoinvestigatethe
modeluncertaintyandbiasrelatedtoEC2web-crushingfunctionusingthecomprehensive
databasethatisexclusivelyfocusedonprestressedconcretebeamswithweb-crushingfailure.
The measured web-crushing strengths from the experimental tests are compared with the
unbiased predicted web-crushing strengths obtained from Eurocode 2. Correlation and
regression analysis was also conducted to expose its dependency on some of the essential
variables affecting web-crushing strength. The model uncertainty and bias related to the
unbiasedEC2designfunctionforpredictingweb-crushingfailurewasfoundtohaveamean
value�� = 1.05and standard deviation�� = 0.15. The derived model factor observations
wereshowntobesensitivetotheamountofshearreinforcement������andbeamwidth��.
Subsequently, the derived model error statistics were used as input to assess the implicit
safetylevelofEC2designfunctionforweb-crushingfailure.Reliabilityassessmentusingthe
FORMprocedurewasconductedtohighlightthesafetyperformanceregimesobtainedfora
limited parametric range of ������where web-crushing failure governs. The concrete
strength,stirrupspacing,yieldstrengthofstirrups,geometricalpropertiesandmodelerror
werealltreatedasrandomvariables.Theresultsindicatedanincreaseinestimatedreliability
index(β)values as shear reinforcement������increases and a decrease in reliability as
concretestrength���increases.
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A0421-Bearingcapacityfittingandunfavorablegeometricdefectsanalysisofsteel
archbasedonmultipleresponsesurfaces
JunlinZhenga,JunLuob,QianqianYina
aMasterstudent,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
bIntermediateengineer,HunanAcademyofBuildingResearch,Changsha410000,China,e-
mail:[email protected]
For a complex failure equation(e.g. implicit and highly nonlinear), the accuracy of the
conventionalresponsesurfacemethodislimitedbythevariationofrandomvariablesandthe
numberofsamplepoints,whichmayleadtotheinaccuracyofthefittingfailureequationand
theinaccurateapproximatedesignpoint.Therefore,manyimprovedmethodsareproposedto
performreliabilityforlargestructure,andthemultipleresponsessurfacemethodisusedto
fitthefailureequationofthesteelarchstructureinthispaper.Geometricimperfectionswill
significantly reduce the stability bearing capacity of steel arch structure. In order to
reasonablydeterminetheunfavorablegeometricaldefectsofsteelarch,themultipleresponse
surfacesmethodbasedonsubspacedivisionisusedtofitthebearingcapacityfunction.Then,
accordingtotheLagrangemultipliermethodoftheextremumofthefunction,thegeometric
defectsdistributionwiththelowestbearingcapacityissolved.Takingthetwohingedcircular
steelarchasanexample,consideringthechangeofparameterssuchastheloadratioandthe
numberofdeviationnodes,thebearingcapacityanalysisresultsarecomparedbetweenthe
proposedunfavorabledefectsdeterminationmethodandtheconsistentmodeimperfection
method.Theresultsshowthat:(1)Themultipleresponsesurfacesmethodbasedonsubspace
ismoreaccurateinfittingbearingcapacityfunction,andthepredictionvalueofthebearing
capacityisclosetotheresultofthefiniteelementanalysis;(2)Thegeometricimperfections
obtainedbyusingthefittingfunctiontocalculatetheextremumaremoreunfavorabletothe
bearingcapacity,andintherangeofparameteranalysis,thecorrespondingbearingcapacity
isabout10%lowerthanthatobtainedbytheconsistentmodeimperfectionmethod.(3)In
the range of parameter analysis, with the increase of the number of deviation nodes, the
difference between the distribution of unfavorable defects based on multiple response
surfaces bearing capacity fitting and the distribution of the consistent defects is further
increased, and the positive and negative deviations of nodes of unfavorable defects
distributionbasedonmultipleresponsesurfacesbearingcapacityfittingaremoreobvious.
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A0423- Structural failure pattern recognition and reliability analysis based on
multi-responsesurfacemethod
ZhaoChena,LinjieZhaob
aMasterstudent,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
bIntermediateengineer,Henaninstituteofarchitecturaldesignandresearch,Zhengzhou
450014,China,e-mail:[email protected]
In order to prove the correctness of the calculation results of the multi-response surface
methodstructureanalysissoftware,thispaperusesthesoftwaretoanalyzeandcalculatethe
space48-bartransmissiontowerstructure.Theauthorcomparesthecalculatedresultsofthe
software with those obtained by Monte Carlo method, line sampling method and subset
simulationmethod.Itisfoundthatthismethodisveryclosetothesystemreliabilitycalculated
by Monte Carlo method, line sampling and subset simulation. The results obtained by this
programaresatisfactory.Moreover,thenumberofstructuralanalysesrequiredbythismethod
isthelowestcomparedwiththeothermethods,whichonlyneeds228.Thisshowsthehigh
efficiency of this method. The traditional failure pattern recognition and structural system
reliability analysis methods have two shortcomings: the main failure pattern recognition
efficiency is low and the joint failure probability calculation of multiple failure modes is
complex.Inthispaper,animprovedsimulationmethodisproposedtoidentifythemainfailure
modes.Usingthismethodtoaclassicalframestructureisanalyzed,anditiscomparedwith
the more widely used one, namely, beta boundary method. The results show that a large
numberofcomponentsneedtobeanalyzedfortheirreliabilityintheprocessofidentifying
majorfailuremodes.However,thismethodonlyneeds56finiteelementanalysestoobtainthe
samecalculationresults.
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International Conference 2018 November 2-4 Tongji University
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A0440- IDENTIFICATION OF PERFORMANCE DEGRADATION MODEL BASED ON
STANDARDWIENERPROCESS
XiaoWanga,ZhenhaoZhangb
aPostgraduate,ChangshaUniversityofScienceandTechnology,e-mail:
bAssociateProfessor,ChangshaUniversityofScienceandTechnology,e-mail:
Wienerprocessmodel isakindofcommonprobabilisticstatisticalmodel,whichhasgood
computational analysis characteristics and can describe the degradation process of non-
monotonesystem.Therefore,itisoneofthemostwidelyusedmodelsinstructuralreliability
modelingbasedonperformancedegradation.Furthermore,theengineeringstructurehasthe
characteristics of randomness, fuzziness and time-varying in the service life. Thus, it is
consideredthattheuseofWienerprocesstodescribethedegradationprocessofstructure
can reflect the actual situation of structural degradation better. In fact, identification of
degradationprocessmodelsisthemostimportantanddifficultinthedegradationprocesses
modeling. In this paper, we use auto-correlation function method and hypothetical test
methodtoidentifymodel.Thefirstmethodisempirical,whichissuitableforallcomponents
tomeasureperformancedegradationatthesametimeandlowprecisionrequirement.Firstly,
wedrawtheauto-correlationfunctiongraphofthewienerprocessbyMATLAB.Secondly,we
collectthedegradationdataoftheconcretedynamicelasticmodulusthatcanbeusedasa
parameterofevaluatingdurability,thenobtaintheauto-correlationfunctionofthedataand
supplementitwiththegraph.Finally,wecomparethegraphicsofthetwo,itcanbeseenthat
they are similar in appearance, so we can preliminarily determine that the degradation
processconformstothewienerprocess.Comparedwiththefirstmethod,thesecondismore
reliable,whichusesprobabilitystatisticsmethodtotestwhetherthedegradationofdynamic
elasticmodulusofconcretesatisfiesthedefinitionofWienerprocess.Firstly,weadoptShapiro
testmethodtoexaminethenormalityofthedatabytheR-Studio;theresultsshowthattheW-
valueiscloseto1andtheP-valueisgreaterthan0.05,itexplainsthatthedataobeythenormal
distribution.Besides,weusethelinearregressionmethodtofitmeanandvarianceofthedata
onthisbasis,theresultsisthatthecorrelationcoefficientRofthemean,ut andthevariance,
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t2 iscloseto1andP-valuenear0,soitisconsideredthatthedegradationdataofdynamic
elasticmodulusadherestoanormaldistributionwithanaverageofut andvarianceof t2 .
Secondly,werespectivelyuseADFtestmethodandLBQtestmethodtoexaminethestability
andindependenceofthedata,theADFresultsreflectthatP-valueislessthan0.05andtheLBQ
resultsdisplaythatP-valueisgreaterthan0.05,itmeansthattheincrementprocessisstable
and independent. In conclusion, we can judge that the concrete dynamic elastic modulus
degradationsatisfiesdefinitionofWienerprocess.Onthisbasis,wecanpredicttheresidual
lifeofthestructureandprovideascientificbasisforthelatermaintenanceandreinforcement
of the structure. In addition, we also can evaluate the reliability of the existing concrete
structuraldurabilityandprovideareasonabledesignbasisfortheproposedstructure,thus
reducetheconstructioncostoftheengineeringstructureatmaximumextentunderensuring
thesafety.
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A0449- A NeW unbiased metamodel method for Efficient reliability analysis of
structureswithmultiplefailuremodes
GuofengXuea,YongshanZhangb
aPostDoc,SchoolofCivilEngineering,GuangzhouUniversity,e-mail:[email protected]
bProfessor,SchoolofCivilEngineering,GuangzhouUniversity,e-mail:
Asawidelyusedmethodforstructuralreliabilityanalysis,themetmodelmethodcanreduce
the computational cost substantially. However, there always exists error due to the
approximation of the metamodel to the Limit state function (LSF), resulting in a biased
estimator of the failure probability. In order to overcome the difficulties of the metamodel
method,theauthorsdevelopedanunbiasedKrigingmetamodelmethod.Thebasicideaisto
formulate the unknown failure probability as a product of the Kriging metamodel-based
failure probability and a correction term which accounts for the error due to metamodel
approximation.ThecorrectiontermisestimatedefficientlywiththeMarkovchainsimulation
byintroducinganintermediateeventwhichistheunionoftheactualfailureregionandthe
metamodel-based failure region. However, practical engineering structures often have
multiplefailuremodes.It’shardtoobtaininitialsamplesfromthefailureregions,whichmakes
it infeasible to perform Markov chain simulation and estimate the correction term. What’s
more,Markovchainsstartfromonefailureregionhasfewchancestojumptoanotherfailure
region.Therefore,contributionsofdifferentfailureregionstothefailureprobabilitycannotbe
properlyaccountedfor. Inordertotacklethedifficultyoftheunbiasedmetamodelmethod
when applied to problems with multiple failure regions, this paper proposes a modified
versionoftheunbiasedKrigingmetamodelmethod.Theproposedmethodconsistsofthree
steps:1)buildsaninitialKrigingmetamodelwithsuchanaccuracythatthemetamodelcan
capturetheglobalbehavioroftherealLSFs,2)proposesanadaptiveclusteringalgorithmto
obtainrepresentativesamplesfromthefailureregions,basedonthebuiltKrigingmetamodel,
3)estimatesthefailureprobabilitywiththeunbiasedKrigingmetamodelmethod.Thefirst
stepisimplementedbyusingthemetamodelconstructionstageoftheMeta-ISmethod.The
Krigingmodelisadoptedasthemetamodelhere,althoughanyothermetamodelisapplicable.
An intial Kriging metamodel is built with a few samples generated by Latin hypercube
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sampling(LHS).ThentheKrigingmetamodelisupdatedsequentiallywithsamplesfroman
importance density constructed based on current metamodel. The update process is
conducteduntil thetargetaccuracy isachieved,whichguaranteesthatrelativeerrorofthe
metamodelisintheorderofmagnitudeof1.Ingeneral,themetamodelwithsuchanaccuracy
can capture the major failure regions. Based on the last updated metamodel, an adaptive
clustering algorithm is employed to identify the failure regions. The Davies-Bouldin (DB)
indexisadoptedastheclusteringvalidityindex.ClusteringthatminimizestheDBindexisthe
optimalclustering.Eachclustercorrespondstoasub-failureregion.Andthecluster’centroid
ischosenastherepresentativesampleofeachoneofthefailureregions.Basedontheobtained
samplesofthefailureregions,thecorrectiontermiscalculatedbyMarkovchainsimulation.
Following the procedure of the unbiased metamodel method, the failure probability is
estimated by multiplying the correction term by the metamodel-based failure probability.
Severalnumericexamplesareprovidedtodemonstratetheproposedmethod.
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A0487- SPARSE PARTIAL LEAST SQUARES REGRESSION-POLYNOMIAL CHAOS
EXPANSIONMETAMODELINGMETHOD
WeiZhaoa,LingzeBub
aLecturer,SchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,150090,China,
e-mail:[email protected]
bPhDcandidate,SchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin,150090,
China,e-mail:[email protected]
To circumvent the curse of dimensionality and multicollinearity problems of traditional
polynomial chaos expansion approach when analyzing global sensitivity and structural
reliability of high-dimensional models, this paper proposes a sparse partial least squares
regression-polynomialchaosexpansionmetamodelingmethod.Firstly,aninitialestimationof
polynomialchaosexpansioncoefficientsisobtainedwiththepartialleastsquaresregression.
Secondly,accordingtotheprincipleofmaximumsparsityundertheallowanceofregression
errorthreshold,polynomialswhichhavestrongcorrelationwiththestructuralresponseare
adaptively retained with the penalized matrix decomposition scheme. Next, an updated
estimationofthepolynomialchaosexpansioncoefficientsisobtainedwiththepartial least
squaresregression.Sobolsensitivityindicesareobtainedwithasimplepost-processingofthe
expansion coefficients. Finally, the metamodel is greatly simplified by regressing with
importantinputs,leadingtoaccurateestimationsofthefailureprobabilitywithoutadditional
computational cost. The results show that with acceptable accuracies, the new method
overperformsthetraditionalcounterpartintermsofcomputationalefficiencywhensolving
high-dimensionalglobalsensitivityandstructuralreliabilityanalysisproblems.
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A0518-GlobaldynamicSeismicReliabilityanalysisforRCFramestructuresUsing
nt-ANN
Da-GangLua,Jia-ShuaiWangb,YanSongc,ZiZhangd
aProfessor,SchoolofCivilEngineering,HarbinInstituteofTechnology,e-mail:
bPhDstudent,SchoolofCivilEngineering,HarbinInstituteofTechnology,e-mail:
cPhDstudent,SchoolofCivilEngineering,HarbinInstituteofTechnology,e-mail:
dPhDstudent,DepartmentofCivilandEnvironmentEngineering,NorthDakotaState
University,e-mail:[email protected]
Globalreliabilityofstructuresbasedonsystem-levellimitstatefunctionsisanefficientand
approximate approach to system reliability analysis for complex structures under dynamic
disaster actions. However, the global limit state variable (GLSV) is generally an implicit
functionofthebasicrandomvariables(RVs).Furthermore,thedimensionofthebasicrandom
variablesisanotherbottleneckproblemtothepracticalapplicationsofthisapproach.Monte
Carlosimulation(MCS)andmeta-modeltechniquesaregoodalternativestoovercomingthese
problems.However,MCSaswellasitsdifferentvariantsrequiresubstantialsamplepointsand
costenormouscomputingresourcesforaccurateestimations.Themeta-modelssuchasANN,
alsohavetheproblemofcurseofdimensionality.Inthispaper,anANNmeta-modelbasedon
number-theoreticpoint-selectionstrategy(NT-ANN)isdevelopedtoanalyzeglobaldynamic
reliability analysis of reinforced concrete (RC) frame structures under seismic actions. To
uniformlyfill thespaceofbasicRVsandreducetherequirednumberofsamplepoints, the
goodlatticepointapproachinthenumbertheoryisutilizedtoreplacetheLatinhypercube
samplingapproach.TwogloballimitstatefunctionsforRCframestructuresareconsidered:
globaldeformationlimitstateandglobaldamagelimitstate.TheBPforwardANNsaretrained
asthemeta-modelsforthetwogloballimitstatefunctions.Atwo-sidedevolutionarypower
spectrummodelconsideringthenon-stationaritiesinbothintensityandfrequencyischosen
tomodeltherandomprocessofthestochasticgroundmotion.Furthermore,therandomness
of structures is also considered. Then, the global dynamic reliability indices for the two
system-levelgloballimitstatesofRCstructuresunderseismicactionsarecalculatedbythe
developedNT-ANNmethod.Theaccuracyandefficiencyoftheproposedmethodareverified
andcomparedbythesubsetsimulationtechnique.
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A0540- Estimating uncertainty in limit state capacities for reinforced concrete
framestructuresthroughpushoveranalysis
Xiao-HuiYua,Da-GangLub
aSchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin150090,P.R.China,e-
mail:[email protected]
bSchoolofCivilEngineering,HarbinInstituteofTechnology,Harbin150090,P.R.China,e-
mail:[email protected]
Inseismicfragilityandriskanalysis,thedefinitionofstructurallimitstate(LS)capacitiesisof
crucial importance. Traditionally, LS capacities are defined according to design code
provisions or using deterministic pushover analysis without considering the inherent
randomnessofstructuralparameters.ToassesstheeffectsofstructuralrandomnessonLS
capacities, ten structural parameters that include material strengths and gravity loads are
consideredasrandomvariables,andaprobabilisticpushovermethodbasedonacorrelation-
controlled Latin hypercube sampling technique is used to estimate the uncertainties in LS
capacitiesforfourtypicalreinforcedconcreteframebuildings.AseriesoftenLSsareidentified
from the pushover curves based on the design-code-given thresholds and the available
damage-controlledcriteria.TheobtainedLScapacitiesarefurtherrepresentedbyalognormal
model with the median mC and the dispersion βC. The results show that structural
uncertainties have limited influence on mC for the LSs other than that near collapse. The
commonlyusedassumptionofβCbetween0.25and0.30overestimatestheuncertaintiesin
LS capacities for each individual building, but they are suitable for a building group with
moderatedamages.AlowuncertaintyasβC=0.1~0.15isadequatefortheLSsassociatedwith
slightdamagesofstructures,whilealargeuncertaintyasβC=0.40~0.45issuggestedforthe
LSsnearcollapse.
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A0549- Study on Mechanical properties and damage assessment for Collided
Concrete
XY.Liua,GH.Wangb,L.Shenc,andRJLia
aSchoolofCivilEngineering,ChangshaUniversityofScience&Technology,Changsha,
410076,China,e-mail:[email protected]
bTheCollegeofCivilEngineeringandArchitecture,HunanInstituteofScienceand
Technology,Yueyang,414000,China,e-mail:[email protected]
cSchoolofCivilEngineering,ChangshaUniversity,Changsha,410022,China,e-mail:
Withtherapiddevelopmentoftransportation,theaccidentsofvehicleshitthesuperstructure
ofbridgeshaveoccurredfrequently.However,theexistingcodesandstandardsdonothave
themechanicalperformanceindexofcollidedconcrete.Atpresent,itisdifficulttoobtainthe
mechanicalpropertiesanddamagedegreeforcollidedconcrete,andthemaintenancedesign
for collided bridges cannot be carried out. In this paper, finite element (FE) numerical
simulation and model tests are employed for assessing the damage degree for collided
concretebasedonAcousticEmission(AE)technology.Firstly,thewholeprocessofcollision
forconcretestandardspecimenissimulatedbyusingthefiniteelementsoftware.Meanwhile,
based on the simulation results, 24 group concrete standard specimens are made and the
concrete falling hammer collision test is conducted with considering different cases. After
comparingtheresultsofcollisionforcetimehistorycurve,stressandpeakstrain.Itisfound
that the values of numerical simulation agree well with the values of model test, and the
correctnessofthenumericalsimulationcanbeverified.Secondly,theAEtechnologyisutilized
for analyzing the damage degree betweencollided concrete and non-collided concrete, the
resultsshowthatthestrengthofcollidedreduceobviously,andthebrittlenesswithangrowth
trend,theabruptchangecharacteristicsofAEcanbeusedtodeterminethestagesofmicro-
crack formation,expansionand destabilization for theconcrete,and thedamagedegreeof
concretecanbereflected.Finally,basedontherelationshipbetweenenergyrateandrelative
stress,thedamagedegreeofcollidedconcretecanbeobtainedaccordingtoderivethedamage
factorforcollidedconcrete.Itcanprovidescientificbasisfordamageassessmentofcollided
concrete.
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A0558-Anovelmachinelearning‐basedmethodtoprotectmemberbucklingfor
squarepyramidspacegridstructure
Qian.Zhanga,Jianguo.Caib,Jian.Fengc
aPhDCandidates,SchoolofCivilEngineering,SoutheastUniversity,Nanjing210096,China.
E-mail:[email protected]
bProfessor,KeyLaboratoryofC&PCStructuresofMinistryofEducation,NationalPrestress
EngineeringResearchCenter,SoutheastUniversity,Nanjing210096,China(corresponding
author).E-mail:[email protected]
cProfessor,NationalPrestressEngineeringResearchCenter,SoutheastUniversity,Nanjing
210096,China.E-mail:[email protected]
A novel model is proposed to determine whether there is member buckling in the square
pyramid space grid structure under the design load condition based on the supervised
machinelearningclassificationalgorithm.Therandomdefectsofthestructurearegenerated
throughtheMonteCarloprobabilisticdesignmethod,andthestatisticalcharacteristicsofthe
structuraldefectsareassumedtoobeythenormaldistribution.Thenthedisplacementofthe
selectedresponsecharacteristicpointsunderthelowervirtual loadcondition(Load1)and
the members buckling state under the design load condition (Load2) are calculated by
ABAQUS for the defective square pyramid space grid structure. The input-output
correspondencebetweentheresponsepointdisplacementandthememberbucklingstateis
established.Inputandoutputdatasetsareestablishedthroughcalculatingalargenumberof
structural model with different defect levels. Then, Support Vector Machine, Naive Bayes
classificationandNearestNeighborwereusedtoanalyzetheaccuracyofthepredictionmodel.
Lastly, the effects of the position and number of response points and the virtual load
conditions on the accuracy of the prediction model are further analyzed, and the optimal
predictionmodelschemeisobtained.
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A0580-Anewfractionalmomentequationsmethodfornonlinearvibrationanalysis
RuijingZhanga,HongzheDaia
aHarbinInstituteofTechnology,Harbin150090,China,e-mail:[email protected]
A novel method based on fractional moment equations and copula moment closure is
proposed to approximate the dynamic response of a stochastic nonlinear systems. The
method is behind the concept that probabilistic density function (PDF) of the response is
capableofcharacterizingthefullrandomcharacteristicsofstochasticresponse.Ourapproach
reliesonthederivationofmomentequationsthatdescribethedynamicsgoverningthetwo-
time statistics. These are combined with a non-Gaussian PDF representation for the joint
response-excitation statistics, based on the copula functions. Through the adopted PDF
representation,wederiveaclosureschemewhichinvolvingthefractionalorderstatisticsof
the response and the closure constraint. The dynamics constraint is also derived directly
through the moment equations. The derivation of PDF is based on the maximum entropy
principleinwhichconstraintshavementionedabove.Numericalexamplespresentedinthe
paperillustratethenumericalaccuracyandefficiencyoftheproposedmethodincomparison
totheMonteCarlosimulationmethodandGaussclosureofintegermoment.
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A0583- A Kriging-HDMR metamodel method for system reliability analysis of
structures
KaixiangZhanga,HongzheDaia
aHarbinInstituteofTechnology,Harbin150090,China,e-mail:[email protected]
Thereliabilityanalysisforrealstructuresthatinvolvemultiplefailuremodesareextremely
complicatedandcomputationalexpensive.Themostchallengingproblemistoidentifysub-
failuredomainsandtoobtainthesample’sinformation.Fromthispointofview,weproposed
anefficientreliabilityanalysismethodforcomplexstructuralsystemsonthebasisofKriging-
HDMRmetamodel.Firstly,thePseudo-MarkovChainsimulationwasemployedtoidentifythe
failuredomains.TheMarkovChainMonteCarlo(MCMC)methodwasthenusedtosimulate
failuresamplesofthesub-failuredomains.Foreachsub-failuredomain,thesamplewhichhas
the maximum PDF among the simulated MCMC samples was selected as the design point.
ThesedesignpointswereemployedasthereferencepointstobuildKriging-HDMRmetamodel
foreachsub-failuredomain,respectively.ByweightedsummingtheKriging-HDMRmetmodel
ofallthesub-failuredomains,aglobalKriging-HMDRmetamodelofthestructuralsystemwas
obtained. Finally, Monte Carlo simulation was used to estimate the failure probability by
callingtheglobalKriging-HDMRmetamodel.Theproposedmethodcansignificantlyimprove
theaccuracyandefficiencyofthereliabilityanalysisofstructureswithmultiplefailuremodes,
whichofferseffectivealternativeforthecommonlyusedmethods.Twonumericalexamples
werepresentedtodemonstratetheproposedmethod.
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A0613- STUDY ON CORROSION FATIGUE RELIABILITY OF STEEL BOX GIRDER
DETAILSOFCABLE-STAYEDBRIDGEBASEDONNEURALNETWORK
CHENJi-gonga,ZHUXunb
aGraduatestudent,CollegeofCivilandArchitecture,ChangshaUniversityofScienceand
Technology,e-mail:[email protected]
bGraduatestudent,CollegeofCivilandArchitecture,ChangshaUniversityofScienceand
Technology,e-mail:[email protected]
Inthispaper,thecorrosionfatiguebehaviorofsteelboxgirderisstudied.Thedirecteffectof
corrosion and the coupling effect of corrosion and fatigue are considered in the reliability
study.Thecorrosionfatigueproblemoflocalwelddetailsofsteelboxgirderofcable-stayed
bridge isstudied fromthepointof time-varying reliability.Aiming at theproblemof time-
varyingreliabilityevaluationofcorrosionfatigueforlocalwelddetailsofsteelboxgirderof
cable-stayed bridge, the following aspects are studied. Study on time-varying model for
corrosionfatigueresistance,theattenuationlawofsteelstrengthduetocorrosionisobtained
firstly,andthentheinfluencelawofcorrosiononthefatiguestrengthofsteelboxgirderis
determined according to the functional relationship between fatigue strength and steel
strength.Onthisbasis,thetime-varyingmodelofcorrosionfatigueresistanceisestablished
accordingtomathematicalstatisticstheory.Forthestudyoftime-varyingmodelofcorrosion
fatigueload,thevariationlawofcorrosiondepthofsteelboxgirderwithtimeisdetermined
firstly,thenthedimensionparametersaremodifiedinthefiniteelementmodelaccordingto
thetime-varyinglawofcorrosiondepth,andthenthetime-varyingstressamplitudeofsteel
boxgirderiscalculatedbasedontheappliedtime-varyingloadofautomobilefatigue.Onthis
basis, according to mathematical statistics theory, the corrosion fatigue load time-varying
modelisestablishedthroughuniformdesignandneuralnetworktechnology.Forthestudyof
time-varying reliability of corrosion fatigue, the explicit function expression of the time-
varying model of corrosion fatigue resistance and load is determined firstly. The explicit
function expression of the time-varying model of corrosion fatigue resistance is obtained
according to the modification of corrosion function to fatigue strength. According to the
response surface regression, the explicit expression for the time-dependent model of
corrosionfatigueloadingisobtained.Thenthetime-varyingfunctionofcorrosionfatigueis
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established by explicit function expression of time-varying model of corrosion fatigue
resistanceandload,andthetime-varyingreliabilityindexofcorrosionfatigueiscalculatedby
FORMmethod.Finally,takingSutongBridgeastheresearchobject,thetime-varyingreliability
analysisofcorrosionfatiguereliabilityofwelddetailsofsteelboxgirderofcable-stayedbridge
is carried out by using the method proposed in this paper, and the sensitivity analysis of
parametersiscarriedout.Throughtheaboveresearch,thetime-varyingmodelsofcorrosion
fatigue resistance and load effect are established, and the expressions of corrosion fatigue
resistanceandloadeffectinthecalculationofcorrosionfatiguetime-varyingreliabilityare
established.Amethodoftimedependentreliabilityanalysisofcorrosionfatigueformembers
of steel box girder of cable-stayed bridge is presented. The proposed theory, method and
algorithm are applied to the actual bridge engineering. The factors affecting the corrosion
fatiguereliabilityofsteelboxgirderofcable-stayedbridgeareanalyzedquantitativelyandthe
sensitivityofparametersisanalyzed.Thetrendanalysisofcorrosionfatigueperformanceof
steelboxgirderofcable-stayedbridgeisgivenrespectively.
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A0644-ANewANALYTICALApproachforSolvingtheFirst-PassageProbabilityof
theContinuousMarkovProcess
ZhenhaoZhanga,MingFangb
aAssociateprofessor,ChangshaUniversityofScienceandTechnology,e-mail:
bPostgraduatestudent,ChangshaUniversityofScienceandTechnology,e-mail:
The analysis of first-passage probabilities in stochastic processes is a key problem in the
evaluationofstructuralreliability.Inthiswork,thecontinuousMarkovprocesswasstudiedin
detail to obtain new methods for solving its first-passage probabilities. First of all the
conventional Poisson process method was used to analyze the first-passage probability of
continuousMarkovprocessanditwaspointedoutthatPoissonprocessmethodcannotsolve
thefirst-passageproblemofageneralcontinuousMarkovprocess.ThentheMarkovproperty
of the continuous Markov process was used to calculate the first-passage probability of a
continuous Markov process. This new method includes the following analysis steps. First
integrate the transition probability density function of the Markov process to obtain the
transitionprobabilitydistributionfunction.Thenbasedonthetotalprobabilityformulaand
the transition probability distribution function, the relation of the probability distribution
functionofthefirst-passagetimeoftheMarkovprocessandtheonedimensionalprobability
distributionfunctionoftheMarkovprocesscanbeobtainedbymathematicaldeduction.And
theonedimensionalprobabilitydistributionfunctionofcontinuousMarkovprocesscanbe
obtainedthroughthetransitionprobabilitydensityfunctionandtheinitialconditionofthe
Markovprocessbyintegration.Thustheprobabilitydistributionfunctionofthefirst-passage
time of the continuous Markov process can be solved finally, by which the first-passage
probability canbecalculatedeasily. Theresults indicate that analyticalexpressions for the
first-passagetimeprobabilitydistributionfunctionofthecontinuousMarkovprocesscanbe
derivedusingelementarymathematicalmethods,throughtheMarkovpropertyoftheprocess.
Theresultinganalyticalsolutiondoesn’trequiretheuseofassumptionsinitscalculations.The
new analytical method based on the Markov property of the continuous Markov process
produceshighlyaccuratesolutions.Finally,asanapplicationexample,acontinuousMarkov
processwasusedtosimulatestructuralperformancedegradation.Itisusedtorepresentthe
time-varying amount of structural degradation at any point in time, leading to a non-
stationarystochasticmodelforthedegradationprocess,whichwillprovidesascientificbasis
foranestimationofthestructuraldurabilityandreliabilityofconcrete,andtheformulationof
arationalfortificationandmaintenanceschemesforconcretestructures.
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A0753- A polynomial element based Galerkin approach for the simulation of
multivariaterandomfields
XufangZhanga,QianLiu,HeHuang
aAssociatedProfessor,SchoolofMechanicalEngineeringandAutomation,Northeastern
University,e-mail:[email protected]
Uncertaintysimulationsrelatedtospatiallyvaryingrandompropertiesrequirethetheoryof
randomfielddiscretization.Itisknownthatarandomfieldindefinitionconsistsofaninfinite
numberofrandomvariablesthatareattachedtoeverypointof thesimulationregion.The
utilityofKarhunen-Loève(K-L)expansionallowsonetorepresent therandomfieldas the
summationofaseriesofdeterministicfunctions.Bythisway,statisticalapproximationofthe
spatially varying random property can be realized by means of a finite number of random
variables.However,theK-Lexpansiondependscruciallyuponanalyticaleigen-solutionsofthe
Fredholmintegralequationofthesecondkind.Especiallywithanemergingrequirementfor
a multivariate random field simulation along with complex geometries, the exact K-L
expansionisseldomapplicableforrealisticengineeringproblems.Tothisend,apolynomial
element based Galerkin approach is introduced in the paper to deal with the integral
eigenvalue problem for complex geometries. To implement, various types of high-order
elementsarederivedbasedonorthogonalpolynomialsinnumericalanalysis.Besides,todeal
withhigh-dimensionalintegralsproducedbythemultivariateGalerkinprojection,theGauss-
type numerical interpolation schemes are presented to approximate the true but
computationally demanding covariance functions. To access numerical accuracy of the
polynomialelementbasedGalerkinapproach,theconvergencerateisassessedbymeansof
global variance and covariance errors. Several examples including the reproduction of
spatially varying fiberglass density field along with the NACA0012 airfoil geometry are
presentedtoillustrateengineeringapplicationsoftheGalerkinapproach.Resultshaveshown
the polynomial element based Galerkin method is effective for numerical simulation of
multivariaterandomfieldsalongwithcomplexgeometriesinvariousengineeringdomains.
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A0771-ConstructionMonitoringfortheHeavyTrussLiftingProject inChangsha,
China
PeiYilina,ZhouSaib,ZhaoYuc
aHunanUniversity,HunanChangsha,China,e-mail:[email protected]
bHunanUniversity,HunanChangsha,China,e-mail:[email protected]
cHunanUniversity,HunanChangsha,China,e-mail:[email protected]
The under constructed Ice-snow Joy World project in Changsha is the largest indoor
amusementparkamongtheworldwhichwasalsotheonlypublicstructurewiththeice-snow
themethatconstructedabovethediscardedhugepit.Theglobalstructureiscompositedby
the 60-m mass concrete supporting columns, the 3×104 -m 2 concrete platform and the
1.8×104-tonsteeltrussroof.Aliftingprojectwasinitiatedtobuildtheroofsystemwhichwas
constructedbythelarge-spantrusseswithhugeself-weight,andthelargecomponentcross-
sectionshasleadingagreatweldingoperationsfortheliftedstructures.Thefirstlylifted600-
tonprimarytrusswasapproximately48-mlong,8-mdeepandwasweldedbytheseriesof
thin-walledboxsteel,whichwasliftedbyfourgroupssteelcablesinsidethesteeltubes.The
integralliftingprocesswasplannedtocompletefor27mhoistingheightwithin6hours.To
evaluate the operation risk and require the practical demands of structure performance
during the construction process, a real-time remote monitoring system with 10-mins
sampling time was designed and implemented to measure the stress status of structural
components. The multiple vibratory-wire strain gauges were deployed in this project to
measureandmonitorthestressesindifferentlocations,wheretengaugeswerearrangedin
the primary truss and eight gauges were arranged at the bottom for each of the two-side
supporting columns with distributed data-acquisition equipment to measure the strain
releasesduringtheconstructionprocess.Theactualtestedstrainmeasurementsshowedthat
theprimarytrussexhibitedtheacceptablelevelsofstrainthatwerebelowsteelyieldinglimits,
whichindicatingthatasafestatuswasperformedbythestructureduringtheliftingprocess.
Andthestressstatusoftwo-sidesupportingcolumnswereconsistentlykeptinacertainrange,
which indicating that a stable lifting operation was investigated without larger tilt and
vibrationorabnormalconditions.Andtheout-of-planemovementswasnotoccurredduring
theliftingprocess.Minorchangesofstressconditionswereinvestigatedfortheprimarytruss
duringthesubsequentboundaryweldingoperation,whilethestressinsupportingcolumns
was continuously diverged within an acceptable range until the welding operation was
completed. The measured stress distribution characteristics was confirmed by the finite
element(FE)modeltoensurethattheconstructionbehavioroftheprimarytrusssystemwas
reliableduringtheglobalprocess.
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A0830-QuantifyingPost-disasterFunctionalityLossesandRecoveryofCommunity
BuildingPortfolios
PeihuiLina,NaiyuWangb
aPost-doctoralresearcher,SchoolofCivilEngineeringandEnvironmentalScience,University
ofOklahoma,USA,[email protected]
bAssistantProfessor,SchoolofCivilEngineeringandEnvironmentalScience,Universityof
Oklahoma,USA,[email protected]
Assessingcommunityresiliencerequiresestimationofpost-disasterfunctionalitylossesand
recovery of its building portfolios. This study proposes a physical-based probabilistic
framework for quantifying the functionality loss and recovery of spatially distributed
buildings within a community, as an integrated system. The framework includes three
modules:(1)First,anovelbuildingportfoliofunctionalitymetric(BPFM)isproposed,which
isameasurable,scalable,andactionableindicatorofabuildingportfolio’scapacitytorespond
and recover from a hazard event. (2) Second, a building portfolio loss estimation (BPLE)
approachisdevelopedtoquantifythefunctionalitylosses(measuredbyBPFM)ofbuilding
portfolios immediately following the hazard probabilistically, by propagating uncertainties
throughouthazardcharacterization,spatialdamageevaluation,andspatialfunctionalityloss
estimation. (3) Third, conditional on the functionality losses quantified in previous step, a
buildingportfoliorecoverymodel(BPRM)isdeveloped.TheBPRMisatwo-levelstochastic
simulation model modeling the building-level restoration as a discrete state continuous
timeMarkovChain(CTMC)andmodelingtheportfolio-levelrecoverybyspatialaggregation
oftheindividualbuilding’sCTMCprocessovertheentirerecoverytimehorizon.Intheend,
theentire frameworkis implementedtoatestbedcommunity—ShelbyCounty,TN,under
scenarioearthquakehazard.
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A0912- Analytical solution for local buckling strength of square CFT columns
subjectedtoeccentriccompression
LONGYu-linga,WANJunb
aAssociateprofessor,DepartmentofCivilEngineering,GuangdongUniversityofTechnology,
e-mail:[email protected]
bGraduatestudent,DepartmentofCivilEngineering,GuangdongUniversityofTechnology,e-
mail:[email protected]
Intheresearchanddesignoflocalbucklingofconcretefilledsteeltubular(CFST)members,
thelocalbucklingcharacteristicsofcircularorsquareCFSTmembersunderaxialcompression
are studied. However, the theoretical and experimental studies on the local buckling
characteristics of CFST members under eccentric compression have not been reported. In
engineering practice, concrete filled square steel tubular columns are widely used as
eccentricallyloadedmembers,andthelocalbucklingcharacteristicsofthesteeltubewallare
notclear.Inthispaper,thelocalbucklingbehaviorofthesteeltubeofconcretefilledsquare
steeltubulareccentricallyloadedcolumnsisstudiedtheoretically.Itisassumedthatboththe
loaded and non loaded edges of the square steel tube columns are fixed constraints, and
consideringtheeffectofconcretefilledinthesteelsheet,thatis,assumingtherigidityofthe
concretefilledinthesteelsheet,thesteelsheetcanonlybuckleoutward.Takelongitudinal1.5
wave(wavelengtha)forresearch,ananalyticalsolutionoflocalbucklingstressofconcrete
filled square steel tubular eccentrically loaded columns is derived by means of energy
variationalmethod.Furthermore, it is foundthat the localbucklingstrengthσcrdecreases
significantly with the increase of width-thickness ratio b/t when the stress gradient is
constant,andthelocalbucklingstressincreaseswiththeincreaseofstressgradientwhenthe
width-thickness ratio is constant. When the stress gradient coefficient is 0, that is, axial
compression, the local buckling coefficient of the steel tube reaches the minimum value of
10.312; when the stress gradient coefficient is 2, that is, pure bending, the local buckling
coefficient of the steel tube reaches the maximum value of 22.713. When concrete-filled
squaresteel tubularcolumnsaresubjectedtouniaxialeccentric loading, the localbuckling
strengthofeachsteelplateofconcrete-filledsquaresteeltubularcolumnsisdifferentbecause
of thedifferentstressstate. Inorder tomaximize theuseof thestrengthofconcrete-filled
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squaresteeltubularcolumns,thelocalelasticbucklingshouldbeavoidedbeforethesteelyield,
theconcrete-filledsquaresteeltubularplatescriticallocalbucklingstressisgreaterthanits
yield strength. Finally, the reasonable width-thickness ratio limits of each steel plate of
concrete filled square steel tubular eccentrically compressed columns with different stress
gradientcoefficientsaregiven.Satisfyingthelimitscanensurethatnolocalelasticbuckling
occursbeforethesteelplateyields,whichcanbeusedasareferenceforengineeringdesign.
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A0915-RiskPrioritynumbersforvariousfailuresinbridges
ChandrasekharPutchaa,JessicaRodriguezb,SubhrajitDuttac
aProfessor,DepartmentofCivilandEnvironmentalEngineering,CaliforniaStateUniversity,
Fullerton,Fullerton,CA92834,USA,e-mail:[email protected]
bGraduatestudent,DepartmentofCivilandEnvironmentalEngineering,CaliforniaState
University,Fullerton,Fullerton,CA92834,USA,
cAssistantProfessor,DepartmentofCivilEngineering,NationalInstituteofTechnoogyat
Silchar,Silchar,Assam,India
Oneoftheimportantandasystematicmethodthatisusedforidentificationoffailuresofany
systemisFMEA(FailureModeEffectsAnalysis).Thisisdonethroughidentificationofthemost
important causes of all the failure modes of the system under consideration. This
identificationcanbeeasilyachievedthroughthedescriptionofallfailuremodesofthesystem
underconsideration.FMEAisbasedontheconceptsofprobabilisticanalysis.Acorresponding
equivalentdeterministicmethodhasbeendevelopedbyDytczakandGinda(2017).Thispaper
describesindetailtheapplicationofthismethodtobridgefailures.Basedonactualdata.The
results are also compared with those obtained using the well known FORM (First Order
Second Moment) method. This will enable the engineers to rank various failures and take
necessarysteps tomitigate therisk.Theseresultswillbeuseful tobothacademicians and
practicingengineers.
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A0944-Reliabilityanalysisofseismiccapacityofshearwallconsideringpossible
tensionfailureandrandomeccentricity
YanbiaoWanga,YouhuaZhaob,YoubaoJiangc
aMasterstudent,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
bMasterstudent,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
cProfessor,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
In2010Chileearthquake,itisfoundthatsomeRCshearwallstructureshavebeenseriously
damaged, which necessitates great significance to study reliability of the structures.
Consideringthefactorsofflange,abdominalreinforcementareaandrestrainededgemembers,
theseismiccapacityreliabilityindexisanalyzedfortypicalshearwallstructures.Firstly,we
usedPKPMandETABSsoftwaretoestablishtypicalshearwallstructuresof15and33stories,
and analyzed the ranges of the load effect ratio values of rectangular section and I-section
shearwallmodelsunderdifferentseismicintensity.Then,theMonteCarlomethodisusedto
calculatereliability indexforshearwallstructureswithdifferentparameters(e.g.sections,
load effect ratios, reinforcements) considering possible tension failure and random
eccentricity.Theinfluencesofrestrainededgemembersofdifferenttypesonreliabilityare
also analyzed. The results show that: (1) the reliability will reduce by increasing the axial
compressionratiofortheshearwallunderthesamedesigneccentricity;(2)thereliabilityof
shearwallwithrestraintofendcolumnisthehighest,andthatwithrestraintofconcealed
column is the lowest; (3)the vertical distributed reinforcements of the shear wall and the
reinforcementsattheendoftheflangewallhaveagreatinfluenceonthereliability,andthe
reliabilityindexoftheshearwallcanbeimprovedlargelybyincreasingtheareaoftheend
reinforcements.
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A0949- Structural failure mode identification and reliability analysis based on
multi-responsesurfacemethod
ZhaoChena,LinjieZhaob
aMasterstudent,SchoolofCivilEngineering,ChangshaUniversityofScienceandTechnology,
Changsha410114,China,e-mail:[email protected]
bIntermediate engineer,Henaninstituteofarchitecturaldesignandresearch,Zhengzhou
450014,China,e-mail:[email protected]
In order to prove the correctness of the calculation results of the multi-response surface
methodstructureanalysissoftware,thispaperusesthesoftwaretoanalyzeandcalculatethe
space48-bartransmissiontowerstructure.Theauthorcomparesthecalculatedresultsofthe
software with those obtained by Monte Carlo method, line sampling method and subset
simulationmethod.Itisfoundthatthismethodisveryclosetothesystemreliabilitycalculated
by Monte Carlo method, line sampling and subset simulation. The results obtained by this
programaresatisfactory.Moreover,thenumberofstructuralanalysesrequiredbythismethod
isthelowestcomparedwiththeothermethods,whichonlyneeds228.Thisshowsthehigh
efficiency of this method. The traditional failure pattern recognition and structural system
reliability analysis methods have two shortcomings: the main failure mode identification
efficiency is low and the joint failure probability calculation of multiple failure modes is
complex.Inthispaper,animprovedsimulationmethodisproposedtoidentifythemainfailure
modes.Usingthismethodtoaclassicalframestructureisanalyzed,anditiscomparedwith
the more widely used one, namely, beta boundary method. The results show that a large
numberofcomponentsneedtobeanalyzedfortheirreliabilityintheprocessofidentifying
majorfailuremodes.However,thismethodonlyneeds56finiteelementanalysestoobtainthe
samecalculationresults.
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MS15: Environmental Effects on the Properties of
Cementitious Materials: Experiments, Modeling and
Simulation
A0526- Experimental Research on Dynamic Characteristics of Crumb Rubber
ConcreteatLowTemperature
GangXUEa,Mei-lingCAOb,XiaoYIc
aPh.D.,Professor,InnerMongoliaUniversityofScienceandTechnology,China,e-mail:
bInnerMongoliaUniversityofScienceandTechnology,China,e-mail:[email protected]
cInnerMongoliaUniversityofScienceandTechnology,China,e-mail:[email protected]
Therubberconcretecaneffectivelyusethewasterubber.Combiningthepulverizedrubber
powder into the concrete can significantly improve its toughness, crack resistance, heat
insulation, noise reduction performance, impact resistance and energy dissipation
performance.Insomehigh-altitudeandcoldregionsofChina,therearemanyairportrunways,
highways, roadbed sleepers and bridge pier, which are subjected to various loads at low
temperature. Systematic study on the dynamic properties of rubber concrete at low
temperatures is urgently needed and will promote the engineering application of rubber
concrete. In the past few years, we carried out some experimental study and theoretical
analysisofthedynamiccompressionperformance,impactresistanceandenergydissipation
performanceofconcretespecimenswithtworubberparticlesizesandfourrubbercontents
atlowtemperaturesof-30°C,inordertoprovideabasisfortheapplicationofrubberconcrete
inpavementengineeringincoldareas.Themainresearchworkofthisarticleisasfollows:
Thedynamiccompressivepropertiesoflowtemperaturerubberconcreteunderthreeloading
rateswerestudied.Thedynamiccompressivestrengthanddeformationpropertiesofrubber
concreteincreasewiththeincreaseofstressrate,andtheyarehigheratlowtemperatureof-
30°Cthanthoseofnormaltemperatureat25°C.Andtheincreaseofstrengthisrelatedtothe
temperature.Thedynamicincreasefactorofrubberconcreteatlowtemperatureislowerthan
that at normal temperature, which shows that the sensitivity of rubber concrete at low
temperatureislower.Withtheincreaseofrubbercontent,thedynamiccompressivestrength
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ofrubberconcretedecreasesandthedeformationperformanceincreasescontinuously.And
the deformation of rubber concrete at low temperature is greater than that at normal
temperature.Moreover,withthedecreaseofrubberparticlesize,thedynamiccompressive
strength of rubber concrete decreases, and the deformation slightly increases. The impact
resistanceofrubberconcreteunderlowtemperatureconditionswasstudied.Comparedwith
roomtemperature,Theinitialandfinalcrackingtimesandductilityindiceofrubberconcrete
at low temperature have a certain degree of decrease. The decrease magnitude of rubber
concrete is smaller at low temperature, and the failure process also becomes smooth,
indicating that the mixing rubber powder into concrete has significant role in improving
ductility at low temperature. Regardless of temperature, the difference between the initial
crackandthefinalcrackisthelargestwhentherubbercontentreaches20%.Theductility
indexofconcretespecimenswith20meshrubberpowderisgreaterthanthatofconcretewith
50meshrubberpowder.Whentheconcreteisincorporatedrubberpowderwithparticlesize
of20meshandcontentof20%,theimpactresistanceofrubberconcreteisthebestatlow
temperature.Becausethediscretenessofdataonimpactresistanceofrubberconcreteatlow
temperature,theWeibulldistributiontheoryisintroducedtostudythedistributionlawofthe
numbersofimpact.TheresultsshowthatWeibulldistributiontheorycanbetterdescribethe
distribution rule of rubber concrete impact times well. The low-temperature energy
performanceofrubberconcretewasstudied.Afterthelowtemperature,thehystereticcurve
ofrubberconcretetendstobefull,andtheenergyperformanceincreasessignificantly.With
theincreaseofthemagnitudeofloadingforce,thelossfactorofrubberconcreteincreases,
andtheincreaserateoflossfactorofrubberconcreteatlowtemperatureissmallerthanroom
temperature.Andwiththeincreaseofrubbercontent,thetotalhystereticenergyconsumption
growth rate of rubber concrete at low temperature of -30°C is faster than that of room
temperature25°C.The loss factorofrubberconcretewith largeparticlesize is largerthan
smallparticlesize.Andgreaterrubbercontentresultsinthemoresignificantrateofincrease
oflossfactor.
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A0542- Engineering application of rubber concrete in airfield pavement and its
performance
XiaoYia,GangXueb
aMaster,SchoolofCivilEngineering,InnerMongoliaUniversityofScienceandTechnology,
Baotou,China,e-mail:[email protected]
bProfessor,SchoolofCivilEngineering,InnerMongoliaUniversityofScienceandTechnology,
Baotou,China,e-mail:[email protected]
In order to explore the engineering application of rubber concrete in airfield pavement,
contrastexperimentsonpavementswithordinaryconcreteandrubberconcretewerecarried
outinNingxiaprovinceofChina.Basedontheresultsoffourexperimentaltestsondamping,
impact resistance, temperature susceptibility and impermeability, rubber concrete shows
better performances than ordinary concrete. The average attenuation ratio and average
dampingratioofrubberconcreteis1.5timesand1.6timesthevalueofordinaryconcrete,
respectively. The lower failure destruction degrees of rubber concrete in the free fall test
showedthebetterimpactresistance.Andthegoodthermalstoragecapabilityandsuperior
deformability were observed in the test of temperature susceptibility. What’s more, the
seepageofordinaryconcreteis3.4timesthevalueofrubberconcretewithin40minutes.In
theexpeditiousfreeze-thawexperiment,after300freeze-thawcycles,thelossofqualityand
relativedynamicmodulusofrubberconcretemetthestandardrequirements.Moreover,the
relative dynamic elastic modulus of rubber concrete is 8.6% higher than that of ordinary
concreteafter300freeze-thawcycles.Alltheadvantagesofrubberconcretearebeneficialto
the applicability of the airport pavement, and it is expected to improve the anti-attack
capabilityoftheairportpavementandenhanceitsprotectionandsafetycapabilities.Italso
solvestheproblemoffreeze-thawdamageofcementconcretepavementinhighaltitudeareas,
andcanmeettheurgentneedsofourcountrytobuildairportpavementsinhighaltitudeareas
oftheplateau.
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A0774-STRAINMONITORINGINCONSTRUCTIONOFLARGE-SCALEREINFORCED
CONCRETEPLATFORM
SaiZhoua,YilinPeib
aCollegeofCivilEngineering,HunanUniversity,Changsha,China,e-mail:
bCollegeofCivilEngineering,HunanUniversity,Changsha,China,e-mail:
TheIce-snowJoyWorldinChangshawasbuiltontopoftheabandonedpit,inwhichthirty-
three concrete-filled steel tube columns were distributed to support the global structural
weightandthereinforcedconcreteplatformwasconstructedtobearvarioustypesofloads.
The long-span platform with an area of 3×104 -m2 was composed of the cast-in-place
prestressedboxconcretebeams,I-beamsandthesteeltrussfloor.Sincethestructuredead-
weight is considerably heavy and the engineering has long construction period, it is
indispensable to carry out long-term strain monitoring on the complex platform structure
during the construction process of the Ice-snow Joy World, in particular the multi-span
continuousgirderbeamswithasectionheightof5m,onwhichexternalforce,deformationor
temperaturestressmayhavesignificantinfluencestocauseadditionalinternalstress.Astrain
monitoringschemewasdesignedandthemeasurementstationsweremainlyarrangedinthe
partswithlargedeformationandsensitivitypredictedbytheoreticalcalculation.Theretotally
contains196strainsensorspre-embeddedinthemainbeamstoobtainaseriesofstraindata
as well as the temperature for monitoring the dynamic status of the structure under
constructionandforfurtherstudies.Thebeamstrainmonitoringsystemcontributestoknow
about the invisible tiny deformation of the components and infer the stress state and
mechanical characteristics along with time change and varying environment. Besides,
temperature sensors were layout in the mass concrete volumes to observe the inner
temperaturedifferences,whichwasaimedtoavoidcriticalcracksduetothesignificantstress
gradienteffectduringcasting.Afteraperiodofdatacollectionandanalysis,someconclusions
canbedrawnfromtheintuitivestrainandtemperaturecurves,whichreflectedtheresulting
stress changes of individual beam under construction and service, and it revealed the
connectionbetweenthestressfieldandtemperaturefieldofmassconcretestructures.Fora
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validationofthereliabilityofthestrainmonitoringsystemandstructuralsafetyperformance,
simulationcomputationusingafiniteelement(FE)methodwascarriedouttocomparethe
peakstrainsbetweenthemeasuredvalueandthesimulationresultduringtheconstruction,
andthemeasuredvaluewasconsistentlywithinadmissiblestress indifferentconstruction
stages,indicatingthatthedesignrequirementwasachieved.Therefore,thestructurestrain
monitoringcaneffectivelyinspectthereal-timestateofstressonsiteandevaluatethesafety
of the structure under construction and service condition, providing basis for practical
constructionandengineeringdesign.
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A0805-STOCHASTICDYNAMICALBEHAVIORSOFCONCRETEREACTIONSYSTEM
INCONCRETESUBJECTEDTOEXTERNALSULFATEATTACK
Tao.Lia,Zhongmin.Suna
aSchoolofEnvironmentandArchitecture,ShanghaiUniversityforScienceandTechnology,
Shanghai200093,China,e-mail:[email protected]
A numerical methodology is proposed in this article to investigate the stochastic dynamic
behaviorsofthecorrosionreactionsysteminconcreteundersulfateattack.First,weprovide
anin-depthdiscussionofthechemicalLangevinequationforelementaryreactionsandthe
deterministicrateequationforcompositereactions.Then,thechemicalLangevinequationfor
compositereaction(CLE-CR)isderivedaccordingtothelawofmassconservationandrandom
processtheory.Thestochastickineticequationforcorrosionreactionsinconcreter(SKE-CRC)
subjectedtosulfateattackisproposedbyapplyingtheCLE-CRtoaseriesofactualsulfate-
induced corrosion reactions. The developed SKE-CRC incorporates the randomness from
systemparameters,initialconditions,andinternalnoiseintothecorrosionreactionsystem.A
seriesofexperimentsareperformedtovalidatetheeffectivenessoftheproposedmethod.The
results calculated from extensive stochastic simulations are expressed in terms of the
likelihoodandextentoftheconcentrationofcorrosionproducts.Theexperimentalresultis
onlyonepossibleoutcomeoftherandomevent,andithasacertainprobability.Theresultsof
thisstudyindicatethatthedynamicalbehaviorsofthecorrosionreactionsysteminconcrete
canbecomprehensivelydescribedifareliableprobabilisticapproachisemployedinsteadof
conventionaldeterministicapproaches.
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A0812-STOCHSTICMODELINGOFSULFATEIONDIFFUTIONCOEFFICIENTATTHE
CONCRETE-SOLUTIONINTERFACE
Tao.Lia,Shanshan.Wanga
aSchoolofEnvironmentandArchitecture,ShanghaiUniversityforScienceandTechnology,
Shanghai200093,China,e-mail:[email protected]
Astochasticmodelofsulfateiondiffusioncoefficientundermultiplefactorsisproposedinthe
paper.BasedonFick'ssecondlaw,theeffectsonthediffusionprocessfromporosity,water-to-
binderratioandstressratioofconcretearecomprehensivelydiscussed.Thecalculatedresults
are compared with the experimental data in the literature. The analysis results of the
stochastic model fit well with the experimental data. This indicates the rationality and
reliabilityof themodel.Comparedwiththeconventionaldeterministicdiffusioncoefficient
model,thestochasticmodelcanreflecttheevolutionprocessofthediffusioncoefficientwith
differentconditions.Andtheprobabilitydensityfunctions(PDFs)ofthediffusioncoefficient
at the different times can be obtained conveniently. In addition, it is also shown that the
randomness of the coupling effect of sulfate and external load essentially comes from the
microstructure porosity affecting its macroscopic diffusion process. Therefore, the random
distribution of porosity can be treated as the main factor considered in the proposed
stochasticmodelofsulfateiondiffusioncoefficient.
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A0814-SELF-HEALINGOFENGINEERINGGEOPOLYMERCOMPOSITESWITHFLY
ASHANDMETAKAOLIN
Li-li.Kana,Bei-bei.Duana,Tao.Yanb
aSchoolofEnvironmentandArchitecture,ShanghaiUniversityforScienceandTechnology,
Shanghai200093,China,e-mail:[email protected]
bSchoolofNavelArchitecture,Ocean&CivilEngineering,ShanghaiJiaotongUniversity,
Shanghai200240,China,e-mail:[email protected]
Self-healingcharacteristicsandmechanismofEngineeredGeopolymerCompositesusingfly
ashandmetakaolin(MFA-EGC)atvarioustensilepreloadingsof1.0%,2.0%and3.0%exposed
toairandwet/drycyclesconditioningregimeswereexperimentallyinvestigated.Theresults
showthatMFA-EGCcombinestheadvantagesoftraditionalECCandgeopolymer,exhibiting
obviousmultiplecrackingpatternandastrain-hardeningbehavior.Thecrackspacingranges
from2mmto5mmandthemaximumresidualcrackwidthisbelow25μm,whichprovidemore
favorableconditionsforself-healing.Afterrehealedsubjectedtotwoenvironments,number
of cracks decreased significantly. The average tensile strain capacity measured can exceed
3.8%,andbothultimatetensilestrainandstrengthofthemajorityspecimensatreloadingare
higherthanthatofvirginspecimenswithoutanypreloading.Airconditioningencouragesthe
self-healing of the MFA-EGC materials. Amorphous aluminosilicate phases with gel-shape
resultingfromgeopolymerizationreactionareverifiedasmainself-healingproductgrowing
inthecrackandPVAfibersurfacebySEM-EDS,XRDandFT-IR,whichmaybeenhancedthe
bondoffiberandmatrixinterface,leadingtotherecoveryofthetensileproperties.
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A0817- PREPARATION AND CHARACTERISTICS OF PVA FIBER REINFORCED
ENGINEERINGED GEOPOLYMER COMPOSITES INCORPORATING METAKAOLIN
ANDFLYASH
Li-li.Kana,Wen-song.Wanga,Jiahao.Wana
aSchoolofEnvironmentandArchitecture,ShanghaiUniversityforScienceandTechnology,
Shanghai200093,China,e-mail:[email protected]
Underactivatingbyalkalinesolutionpreparedbysodiummetasilicateandsodiumhydroxide,
thepreparationofEngineeredGeopolymerCompositesusingflyashasthemainrawmaterial
and metakaolin as auxiliary material was studied, and the performance of uniaxial direct
tensileandcharacteristicof thegeopolymerwerealsoexplored.Theresultsshowthat the
geopolymer has good multi-cracking behavior after uniaxial direct tensile test. The
distribution of cracks is uniform, and the crack spacing is in the range of 2-5mm, and the
average width of residual cracks is about 25μm. The tensile strength for the optimum
proportionat3d,7dand28dwas3.2MPa,3.7MPaand3.8MParespectively,andthetensile
straincouldbeupto6.8%,6.4%and5.2%respectively.Theorderofinfluenceoffactorson
thetensilepropertieswasasfollows:curingtemperature>metakaolincontent>fibercontent.
Through the three-point bending and the single-crack tensile test, it is shown that the
calculated pseudo-strain hardening (PSH) indexes is consistent with the trend of ultimate
tensilestrainbytheuniaxialtensiletest,whichcanwellexplainthehighductility.Theresults
of XRD, FT-IR and SEM show that a large number of amorphous geopolymeric gel were
producedduringthegeopolymerizationreaction,coveringaroundsphericalflyashparticles,
andthesymmetricstretchingAl-O/Si-ObondsandSi-O-Sibendingbondwereobserved.
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A0953-Multi-PhaseModellingofMulti-speciesTransportinCementitiousMaterials:
IncaseofElectrochemicalRehabilitation
Qing-fengLIUa,Li-xuanMAOb,ZhiHUc
aAssociateProfessor,StateKeyLaboratoryofOceanEngineering,ShanghaiJiaoTong
University,e-mail:[email protected]
bMPhilresearcher,StateKeyLaboratoryofOceanEngineering,ShanghaiJiaoTong
University,e-mail:[email protected]
cMPhilresearcher,StateKeyLaboratoryofOceanEngineering,ShanghaiJiaoTong
University,e-mail:[email protected]
Existing reinforced concrete structures experience severe durability degradation when
subjected to alkali–silica reaction (ASR) and chloride attack. A special electrochemical
rehabilitationtreatment,containinglithiumcompoundanolyte,hasbeendevelopedtodrive
lithiumionsintoconcreteaswellasremovechloridessimultaneously,formitigatingboththe
ASR-induced cracks and the chloride-induced corrosion. Good performance of introduced
lithiums in controlling ASR-induced expansion has already been proved. Unfortunately, the
migration mechanism of lithium in concrete under an external electric field is seldom
investigated in existing literature. In this study, with help of the “double-multi” model, the
efficiency of impregnation of lithium ions and simultaneously the removal of chloride ions
throughaspecificelectrochemicaltreatmentarenumericallyevaluated,whichresultsintothe
distributionprofilesofalltypicalionicspecies.Theheterogeneousconcretemodelexamines
theaggregateeffect,especiallyontheinteractionwithlithiumswhicharesupposedtomitigate
ASR. The ionic interaction between different species and the electrochemical reaction at
electrodes are also considered. Through a relative thorough modelling of multi-phase and
multi-species,asystemicparametricanalysisbasedonaseriesofsignificantfactorsduring
electrochemical treatment (e.g., current density, treatment time, temperature, cathode
positionandconcentrationof lithiumsolution)revealssomeimportanttendenciesof ionic
electromigrationinconcrete,whicharesupposedtoguidethefieldapplication.
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A0966-ResearchonMoistureTransportofCement-basedMaterialsBasedonLow
FieldNuclearMagneticResonance
HaitaoZhaoa,XiaWub,YuyuHuangc
aAssociateprof.,HohaiUniversity,e-mail:[email protected]
bPostgraduatestudent,HohaiUniversity,e-mail:[email protected]
cPostgraduatestudent,Hohai University,e-mail:[email protected]
Themicrostructure testofcement-basedmaterialsbasedonNMR is conducted. Under the
conditionsofdifferentwatercementratio,ratioofaggregatetocement,silicafumecontent
andSAPcontent,thevariationofthemostprobableapertureandporosityofcement-based
materialsareresearched.Theresearchshowsthatthemostprobableapertureandporosity
ofsampleswithwater-cementratiosof0.5and0.6increaseby2.22nm,7.16nmand4.56%,
9.09%,respectively.WhenS/Cis1,theporosityofsampledecreasesby3.85%.Theincrease
ofsilicafumecontentcanreducethemostprobableapertureofthesample,butincreasethe
porosity.Whenthesilicafumecontentis5%,10%,theporosityincreasesby2.73%,3.83%
respectively. If thesample isdopedwithSAP, themostprobableapertureandporosityare
increasedwhenthecontentis0.15%,andwhenthecontentis increasedto0.3%,themost
probableapertureandporosityarereducedby4.01nm,1.12%respectively.Itcanbefoundto
playagoodinternalmaintenanceroleinanappropriateamount.Basedonone-dimensional
frequency coding technology, the moisture transfer test of cement-based materials is
conducted.Themoisturedistributioncurvesunderdifferentfactorsareobtainedthroughone-
dimensionalfrequencycodingtests.Itisfoundthatthesilicafumereducesthefluidityofthe
slurry, so the internal distribution of the sample is not uniform, water distribution curve
fluctuates up and down. Absorption height h and water volume per unit area i of sample
increase rapidly first and then slowly with time. The growth trend is consistent with the
variationofporosity.Whenwaterabsorptiontimeis7d,handiofthesampleswithwater-
cementratioof0.6arethelargest,51.97mmand9.48mm3/mm2.Basedontheexperimental
results, key parameter models for water transport are constructed. The models of water
volumeperunitareaandheightofwaterabsorptionunderdifferentfactorsareconstructed.
Basedontheexistingmodel,modelsareestablishedbetweensorptivityS,capillarycoefficient
kandmicrostructure,andtherelationshipbetweenSandkisdiscussed.Itisfoundthatthe
ratiobetweenSandkcanbeexpressedapproximatelyasthetwotimesoftheporosity.The
saturationdistributionandtheBoltzmanntransformationofthemoisturedistributioncurve
are calculated, and then the moisture diffusion coefficient is calculated using the existing
model.Thediffusioncoefficientmodelunderdifferentinfluencefactorsisfinallyobtained.
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MS16: Fluid-Structure Interactions and Flow-Induced
Motions
A0159- Wind-induced cladding and structural loads on low-rise buildings with
4:12-slopedhiproofs
ShuaiShaoa,YujiTianb,QingshanYangc,TedStathopoulosd
aBeijing’sKeyLaboratoryofStructuralWindEngineeringandUrbanWindEnvironment,
SchoolofCivilEngineering,BeijingJiaotongUniversity,Beijing,China,e-mail:
bBeijing’sKeyLaboratoryofStructuralWindEngineeringandUrbanWindEnvironment,
SchoolofCivilEngineering,BeijingJiaotongUniversity,Beijing,China,e-mail:
cSchoolofCivilEngineering,ChongqingUniversity,Chongqing,China;Beijing’sKey
LaboratoryofStructuralWindEngineeringandUrbanWindEnvironment,Beijing,China,e-
mail:[email protected]
dCentreforZeroEnergyBuildingStudies,DepartmentofBuilding,Civil,andEnvironmental
Engineering,ConcordiaUniversity,Montreal,Canada,e-mail:[email protected]
The characteristics of wind-induced cladding loads on building surfaces were examined
regardingdifferentparametersofroofshapes,buildingplans,horizontaldimensions,etc.A
wind tunnel experimental study for low-rise buildings with 4:12-sloped hip roofs was
performedinasimulatedopenterrainexposureattheBuildingAerodynamicsLaboratoryof
ConcordiaUniversity,Montreal,Canada.Furthermore,finite-elementanalysis,appliedtothe
experimentalpressuredata,wascarriedoutinordertoinvestigatestructuralforcefeatures
formainwindforce-resistingframes.Three-dimensional linearcomputationalmodelswith
andwithoutcladding(bareframes)withdifferentstiffnessratiosandconnectionconditions
of structural members influencing the wind load sharing path were considered. Moreover,
comparisons between cladding/frame loads obtained by using experimentally measured
pressuresandtheircounterpartsevaluatedbyusingAmericanwindloadprovisionsforgable
rectangularroofsindicatesignificantreductions.Thesecomparativestudiesareexpectedto
beinstrumentalforfuturedevelopmentofwindcodeandstandardprovisions.
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A0442-ApplicationsofImmersedBoundaryMethodsinHydraulicModeling
NingZhang,AdamOlera,SusanRegmia,ArunYadava
aDepartmentofChemical,CivilandMechanicalEngineering,McNeeseStateUniversity
Two immersed boundary methods (IBMs) have been developed for implementing
levees/floodgates and 1-D rivers/streams in hydraulic modeling. The IBMs have been
originallydevelopedinCFDsimulationforflowsovermovingobjectsorobjectswithcomplex
shapes, where the immersed boundaries of the objects do not coincide the grid points. In
regionalscalehydraulicmodeling,becausethegridsizecouldbemuchlargerthanthewidths
ofthelevees/floodgatesandsomeoftherivers/streams,thelocationsoftheleveesandrivers
couldoftenlocatein-betweengridpoints.Itisnotaccurateforthetraditionalimplementation
byplacinghigherorlowerlandelevationsonthegridpointstorepresentthelevee/floodgates
and streams. Therefore, IBM becomes a good candidate for this type of modeling and
simulations.Thanksto theIBM, thestructure in-betweenthegridpointscanbeaccurately
realized, and the new implementation presents some advantages over the traditional
implementation.TheIBMimplementationalsomakesitpossibletosimulationscenariosuch
astheleveecollapsingandbreachingduringthefloods,whichitisdifficult,ifnotimpossible,
forthetraditionalapproachtoachieve.Inthisstudy,thelevee/floodgateandonestreamwere
implementedusingtheIBMs,andthesimulationresultswerecomparedtotheresultsfrom
thetraditionalmethodforvalidation.Severalfloodingscenariosweresimulatedtoinvestigate
theeffectsofstorm-surgefloodtothecoastalwetlands.
Engineering Mechanics Institute
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A0747-NonlinearParametricVibrationAnalysisofRadialGates
SiyuanWua,ZhengzhongWangb
aDoctoralCandidate,StateKeyLaboratoryofDisasterReductioninCivilEngineering,Tongji
University,e-mail:[email protected]
bProfessor,ColdandAridRegionsWaterEngineeringSafetyResearchCenter,Northwest
A&FUniversity,e-mail:[email protected]
Inthiswork,basedondynamiccharacteristicsofradialgates,anonlinearvibrationequation
oftheradialgatearmisestablished.Excitationconditionsofprimaryparametricresonance
and subharmonic parametric resonance are obtained by using multiple scales method and
numericalmethod.Theparameteranalysisshowsthat:comparingwithtraditionalcalculation
method of dynamic instability region division, the presented method is more suitable to
analysis of parametric vibration for radial gates as considering the end moment, vibration
duration and amplitude. The vibration amplitudes of arm increase with the increase of its
lengthandexcitationamplitude,aswellasthedecreaseofarminclinationangle.Moreover,
theparametricresonanceiseasiertobeexcitedanditsfrequencybandwidthisbroadened
withtheinitialendmomentincreasing.Sincethevibrationresponseofthearmisinfluenced
bythenonlineartermintheequation,thedampingeffectislimited.Inthefurtherresearchof
vibration reduction control, energy transfer method (e.g. tuned mass damper) should be
adoptedtoachievevibrationreductioncontrol.
Engineering Mechanics Institute
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197
A0785-ModeinteractionsofDEEP-SEAriserINShearflow
ZhiqiangWUa,YuancenWanga,GuoqiZhanga
aTianjin,SchoolofMechanicalEngineering,TianjinUniversity,e-mail:[email protected]
Vortex-induced vibration (VIV) is the main problem for in-service deep-sea risers. VIV is
essentially a nonlinear, self-excited and self-limited multi-degree-of-freedom resonance
response due to the nonlinearities either in structure or fluid. For example, the lock-in
response,hysteresis,displacementjump,bifurcationandchaos.Thepresentexperimentaland
finiteelementanalysis(FEA)methodscanmeasureandcalculatetheresponsecharacteristics
ofrisersatspecificflowvelocity.However,itisratherdifficulttoinvestigatethecontinuous
change of VIV response of riser in larger velocity ranges. Based on the Van der Pol wake
oscillator model, the VIV cross-flow governing equations of the riser fluid-structure
interactionsysteminshearflowareestablished.ThenthesimplifiedMDOFmodelwith15th-
ordermodesisderivedbyGalerkinmethod.Itsbifurcationdiagramisobtainedbyusingthe
method of Poincaré mapping for the velocity of ocean current in a wide range. The
characteristics of typical response are analysed based on time history, phase diagram,
Poincaré section and frequency spectrum. It is found that there are various phenomena of
modeinteractioninthesystem,including1:3internalresonance,non-internalresonanceand
multistable phenomenon. Such as periodic solution and almost periodic solution coexist,
periodic solution and periodic solution coexist, and almost periodic solution and almost
periodicsolutioncoexist.Thecharacteristicsofthesephenomenahaveimportantreference
valuefordesigningthecontrolleraboutVIV.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
198
A0788-SuppressingVortex-Induced-VibrationUsingBroadbandPassiveTargeted
EnnergyTransfers
ZhiqiangWUa,GuoqiZHANG,YuancenWANG
aTianjin,SchoolofMechanicalEngineering,TianjinUniversity,e-mail:[email protected]
The passive and nonlinear targeted energy transfers induced by resonant interactions
betweenasingle-degree-of-freedomnonlinearenergysink(NES)anda2-DOFvortex-induced-
vibration(VIV)modelofacylinderisinvestigated.ItisshownthatpartiallysuppressVIVby
passivelytransferringvibrationenergyfromthecylindertotheNESinaone-wayirreversible
fashion.NumericalparametricstudiesidentifythreemainmechanismsforsuppressingVIV:
periodicresponse,quasi-periodicresponseandchaoticresponsesuppressionmechanisms.
WeinvestigatethesemechanismsbothnumericallybyWaveletTransform(WT)andPoincare
map method, analytically by a complexification- averaging technique. Each suppression
mechanism involves strong 1:1 resonance capture during which the NES absorbs and
dissipates a significant portion of energy fed from the fluid flow to the cylinder. Failure of
suppressionisassociatedwithrestoringtheunderlyingtriggeringmechanismofinstability,
whichisaseriesofsuperharmonicresonancecapturesfollowedbyescapesfromresonance.
Finally, using a numerical continuation technique, we perform a bifurcation analysis to
examine sensitive dependence on initial conditions and thus robustness of instability
suppression.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0972-AcTIVELY-CONTROLLEDTurbulenceSIMULATIONSANDTHEIREffectson
THEAEROELASTICPROPERTIESOFTYPICALBRIDGEDeckSECTIONs
YuchaoLva,JinxinCaob,YaojunGec
aMasterstudent,TongjiUniversity,e-mail:[email protected]
bAssistantprofessor,TongjiUniversity,e-mail:[email protected]
cProfessor,TongjiUniversity,e-mail:[email protected]
Asoneofthemostadvancedexperimentaltoolstoreproducethenaturalturbulence,anewly-
built actively-controlled multi-fan wind tunnel facility was employed to investigate the
turbulenceeffectsonflutterderivativesandcriticalwindvelocityoftypicalbridgedecksin
this paper, through the sectional model test approach and the free-vibration identification
methodforflutterderivatives.Thesimulationofturbulentflowfieldsincludingnarrow-band
andwide-bandoneswithdiverseturbulenceintensitiesandintegrallengthscalesisachieved,
whichisdifficultforgrid-generatedturbulenceinconventionalboundarylayerwindtunnels.
Threerepresentativesections,includingathinflatplate,astreamlinedsingle-boxgirder,and
astreamlinedtwin-boxgirderwithacentralslotwereconsideredinthisstudy.Theresults
tend to indicate that turbulence has significant effects on each deck section, meanwhile
turbulence intensity and integral length scale each has respective influence on flutter
oscillationsofbridgedecks.Thegeneralconclusionseemstobethatthemorestreamlineda
sectionis,themoresensitivetoturbulenceitsflutterderivativesare.Atthesametime,flutter
critical wind velocities have been recorded. It is found that the critical wind speeds under
small turbulence intensities are larger than those under the smooth flow, yet under large
turbulence intensities theresults turn to theopposite. With the increase in integral length
scales,thefluttercriticalwindspeedsforallthreesectionswillgraduallydecreaseorincrease
until they equals the critical wind speed values under the smooth flow. Similar to flutter
derivatives,fluttercriticalwindspeedsofstreamlinedsectionsseemtobemoresensitiveto
theturbulence.Inaddition,fluttercriticalwindspeedsbasedonthetwodegree-of-freedom
coupledflutterequationwerecalculatedusingtheflutterderivativedataidentifiedinthetests.
Thecalculatedresultsarewellagreedwiththemeasuredones,whichverifiesboththeflutter
derivativesandcriticalwindspeedsfromtheexperiment.
Engineering Mechanics Institute
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MS17: Stability and Failure of Structures and Materials
A0149- FREQUENCY ANALYSIS FOR VIBRATING BENDING BEAMS VIA A NEW
STATICAPPROACH
ZhenyuChena,C.W.Limb
aPh.D.student,CityUniversityofHongKong,e-mail:[email protected]
bProfessor,CityUniversityofHongKong,e-mail:[email protected]
The natural frequencies of different vibration modes are useful for the understanding of
mechanicalpropertiesofengineeringstructural systems. Thisstudypresentsanewstatic
approach for solving some free vibration structural systems to determine the natural
frequenciesofbeammodelsunderdifferentboundaryconditions.Tothisend,itisobvious
thatanystaticstructuralsystemscanbeconsideredasspecialcasesofmoregeneraldynamic
structural systems. For vanishing time-depended variables, the governing equations of
motion can be reduced to static problems. Starting with the basic governing equation for
beamssubjecttoaharmonicloadandrestingonelasticfoundation,thegoverningequation
forbendingissolvedandapplieddirectlytoyieldthefreevibrationsolutions.Specifically,the
key idea is to assume a positive or negative generalized elastic parameter using the static
approachtocorrespondto therealand imaginary frequencyparametersvia freevibration
analysis,respectively.Consequently,anappropriatenegativeelasticfoundationparameteris
determined and the natural frequencies can be obtained. Its basic assumption is in the
presenceofaconcentratedload,thedeflectionofabeambecomesinfinitewhenthestiffness
approacheszero.Acomparisonwithrespecttoclassicalfreevibrationsolutionsispresented
andexcellentagreementisillustrated.Furthermore,fastnumericalconvergenceofthenew
approachhasalsobeendemonstrated.Thisstaticapproachforfreevibrationproblemscan
beextendedtothedynamicsofmorecomplicatedstructuralsystems.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
201
A0247-HAZARD-INDEPENDENTSTUDYOFTHESTABILITYSENSITIVITYOFTHE
LOWRISEFRAMESYSTEMSSUBJECTEDTOTHEEXTREMELOADINGCONDITIONS
P.Dahala,C.Mullenb
aPh.D.Student,UniversityofMississippi,e-mail:[email protected]
bAssociateProfessor,UniversityofMississippi,e-mail:[email protected]
From the scenarios of different hazardous events (Hurricane, Flood, Earthquake, Tsunami,
Blast,Impactetc.),aneedtoaccountforthepossibledamageisgettingutmostimportance
whileinvestigatingthestabilityofbuildingstructures.Thispaperaimstoprovideaframework
to establish a comparison of stability sensitivity of the frame systems (Steel and RC) in
different levels when subjected to the extreme loading conditions. As an effort to avoid
cumbersomecalculationsassociatedwithparticulardamageevents, theworksattempts to
provide a hazard – independent approach for the application of damaged conditions.
Regardless of the event that characterizes specific damage states, significant damage to
structuralmemberstypicallyreducestherespectivestiffnessoftheelement.Thisprincipleis
utilizedinthehazard–independentdamageapproachbysimplyreducingsectionmoduliof
thetargetedstructuralmemberwithrespecttolateralloaddirectioni.e.,thestiffnessalong
the direction of lateral loading is investigated. This procedure results in a weakened, or
softened,structuralsystemthatisusedtoapproximatetheimpactonstiffnessingloballevel,
andthusthestabilityofoverallsystem.TheworkdoneforthestabilitysensitivityofLowrise
steelmomentframeswaspresentedinEMIConference2017heldinSanDiego.Itisextended
furthertoRCmomentresistingframesandcomparisonofsomeresultsweredemonstratedin
EMI Conference 2018 at MIT. The work accounts for the geometric non-linearities of the
structuralmembersandthesystemasawhole.Proceedingfurthertomakeittomorerealistic
scenario,theresultsfrom3DassemblyofbothRCandSteelFrameswillbediscussed.AISC
approachtosofteningofsectionmoduliformemberstoaccountforplasticresidualstresses
andthateffectoflocalizedplasticityatthesectionandmemberlevelwillbeinvestigated.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0332- ACharacterization of nonlinear constitutive behavior of ceramic-based
compositeusingdigitalimagecorrelation
JIXiaohuiaHAOZiqingaLiuLiua*,
aSchoolofAerospaceEngineering,BeijingInstituteofTechnology,Beijing100081,PRChina
The tensile and compressive behavior of the ceramic matrix composite (CMC), were
investigated in varying orientations relative to the 0/90 woven carbon fibers. The ratio of
sheartonormalstresswasabout1-3.73,dependingonthefiberorientation.Thenon-linear
stress–strainbehaviorundercombinedtensileandshearstressandthelinearelasticbehavior
under compression load were determined through full-filed deformation measurement
technique. The coupling between normal and shear stress of the 2D-woven CMC under
proportionalloadingconditionswereidentified.Theoff-axistensiontestresultsshowthatthe
evolutionrateofdamageisacceleratedunderthecorrespondingcombinedbiaxialtensionand
shear loads.Anovelgeneralizednonlinearstress-strainconstitutiverelationship isderived
using the complementary strain energy density function and the material properties have
beendeterminedthroughtheappliedstressandDICmeasuredstrain inmaterialprincipal
coordinate using the least square regression. The nonlinear coupling between tensile and
shearstresshasbeenconsideredintheproposedmodel.Itisdemonstratedthatthepredicted
stress-strainbehaviorunderoff-axisloadingagreeswiththeexperimentalmeasuredbehavior
verywell.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
203
A0380- PLY-GAP EFFECTS ON BUCKLING BEHAVIOR OF COMPOSITE CONIC
BARRELBYAUTOMATEDFIBERPLACEMENT
TianliangQINa,MufengDUANb,JifengXUc
aSeniorEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresandComposite
Materials,BASTRI,COMAC,e-mail:[email protected]
bEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresandComposite
Materials,BASTRI,COMAC,e-mail:[email protected]
cDeputyChiefEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresand
CompositeMaterials,BASTRI,COMAC,e-mail:[email protected]
Automated fiber placement (AFP) is increasingly used in the manufacturing of aircraft
compositestructures,since it isaprocesscapableofqualityensuranceandcostreduction.
However, duo to the geometric effects, ply-gaps inevitably occur in the process of
manufacturingcompositeconicbarrelwithfiberreinforcedplies.Asply-gapswouldreduce
themechanicalpropertiesofthestructures,suchasstiffnessandstability,itisnecessaryto
establishananalysismethodtoinvestigatetheply-gapeffectsforcompositeconicbarrel.A
methodcombiningtheanalyticalsolutionwiththefiniteelementanalysisisproposedinthis
paper. First, the equivalent mechanical properties of the ply with gaps were calculated
analytically.Then,fieldvariableswereusedinthefiniteelementmethodtorelatethevariable
gaps with the ply equivalent properties in the barrel. The finite element models of AFP
composite conic barrel under tensile, compressive and shearing loads were established to
perform the linear buckling analysis. The buckling loads and their corresponding buckling
modesforthecompositeconicbarrelswithandwithoutply-gaps,respectively,werecompared
tostudytheply-gapeffectsonthestiffnessandstability.Further,ply-gapdistributionsinAFP
composite conic barrel were rearranged, theoretically, to evaluate how the stability can be
improved.Theanalysisresultsindicatedthattheply-gapscanobviouslyreducethebuckling
loadsandchangethebucklingmodesofcompositeconicbarrelundertensile,compressive
andshearingloads.Adequateply-gapwidthcontrolanddistributionareeffectivefactorsto
improvethestabilityofcompositeconicbarrelmanufacturedbyAFPprocess.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
204
A0384- Seismic Performance of Unreinforced Masonry Walls with Boundary RC
Frame
You,Young-Chana,Kim,Min-Sunb,Lee,Hyun-Jeeb
aSeniorresearchfellow,KoreaInstituteofCivilEngineeringandBuildingTechnology,e-mail:
bResearcher,KoreaInstituteofCivilEngineeringandBuildingTechnology,e-mail:
[email protected],[email protected]
Koreangovernmenthasbeenintensifyingthebuildingseismicregulationsforreducingthe
possible seismic damage of the buildings, and it is especially accelerated after Gyeongju
Earthquakein2016.Oneofthemistowidenthescopeofbuildingsthatreviewseismicdesign
conformity when a building permit is granted. But the mandatory seismic design for the
buildingswasstillrestrictedtothreestoriesorhigher,1,000m2ormoreuntil2016.Andat
thesametime,itwasannouncedthatitwouldbeexpandedtomorethan2storiesor200m2
byDecember2017.Ontheotherhands,mostofthedetachedhousesorlow-riseresidential
buildings have been constructed using unreinforced masonry wall in Korea. These
conventionalunreinforcedmasonrywallstructureswerereportedtobevulnerabletoseismic
activity, causing lots of casualty and property losses from the previous earthquake. The
reinforced masonry wall structures are considered to be a good engineering solution
mechanically, but it will take many years to prepare and distribute all of the industry's
infrastructure including structural design, fabrication, and construction to the market. The
purposeofthisstudyistoinvestigatetheseismicperformanceofunreinforcedmasonrywalls
whichisreinforcedwithboundaryRCframetocheckthepossibilityofreplacingreinforced
masonrywallstructures.BoundaryRCframecomposesofonetie-beamandtwotie-columns
in this study. Two specimens are prepared, with the same overall dimension and material
properties. 1st test specimen represented a typical unreinforced masonry wall and 2nd test
specimenwasreinforcedwithboundaryRCframeonthe1sttestspecimenadditionally.Cyclic
loading test was carried out to compare the seismic performance of two different test
specimens.Fromthetestresults,itwasfoundthatfailuremodeofunreinforcedmasonrywall
changed from ‘fragile’ to ‘ductile’ fundamentally by the installing of boundary RC frame.
Additionally, the increased maximum loads of the test specimen with boundary RC frame
correspondingtothesameloadingschedulesresultsingreatincreasingofenergydissipation
capacityabout2~4times.Finally,itwasconcludedthatinstallationofboundaryRCframeon
unreinforced masonry wall can be a good alternative measure for the replacement of
reinforcedmasonrywallsstructureinKorea.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0473- characterization for COMPRESSION-SHEAR COMBINED PROPERTIES of a
compositematerial
TirenHea,LiuLiub*,JifengXua
aBeijingKeyLaboratoryofCommercialAircraftStructuresandCompositeMaterials,BASTRI,
COMAC
bSchoolofAerospaceEngineering,BeijingInstituteofTechnology,Beijing,China
Ascompositematerialshavebeen increasinglyused forprimarystructuresoncommercial
airplane,theabilitytomeasuretheircomplexmechanicalpropertiesefficientlyandtoanalyze
their failuremechanismwithhighfidelitybecomesevenmoreimportant. Inthisstudy, the
nonlinearconstitutivelawforIM7/8552fiber-reinforcedunidirectionalcompositematerial
undermulti-axialloadshasbeenidentified,andfurthermorethefailurecriterionandmodes
have been discussed accordingly. First, improved short beam shear (SBS) tests were
performed,andthedatarecordedbydigitalimagecorrelation(DIC)techniquewasusedto
characterizethecoupledcompression-shearstress-strainrelationship.Thenacompensation
scheme by finite element model updating (FEMU) method was employed to approach the
materialconstitutiveparametersthroughtheprocessofcorrectingtheparametersiteratively
untiltheagreementofsimulatedFEMresultswiththemeasuredDICstrainfield.Atlast,the
uncertainties in DIC data reconstruction and the covariance matrix of the extracted
constitutive parameters are discussed too. To demonstrate its advantage, the proposed
nonlinearconstitutivelawwasusedtoanalyzedeformationmechanismandtosimulatethe
failuremodes.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
206
A0586-BUCKLINGOFBEAMSSUBJECTTOINFLUENCEOFSURFACESTRESSES
FengLinaandY.Xiangb
aResearchAssistant,SchoolofComputing,EngineeringandMathematics,WesternSydney
University,LockedBag1797,Penrith,NSW2751,Australia
bProfessor,SchoolofComputing,EngineeringandMathematics,WesternSydneyUniversity,
LockedBag1797,Penrith,NSW2751,Australia
The micro-electromechanical systems (MEMS) or nano-electromechanical systems (NEMS)
areminiaturizedstructureswithmicroornanolengthscaledfeatures.Insuchstructures,the
existenceofsurfacestresseshasbeenreportedwhichmaygreatlyinfluencethemechanical
behavioursofsuchstructuresandshouldnotcannotbeignored.Thesurfacestressesmaybe
eitherinducedbymismatchingofthematerialpropertiesbetweenthesurfacelayerandthe
underlyingbulkmaterialsorbytheforeignadsorbateonthesurfacelayers.Inthisstudy,the
bucklingbehavioursofthebeamsincludingsurfacestresseffectsareinvestigated.Thebulk
core materials of the beams are assumed to be isotropic and the top and bottom layers of
beams are covered with atomic thin surface layers and are subject to compression. The
Reddy’sthirdordersheardeformablebeamtheoryisemployedtoderivedthetotalpotential
energy functional of the beam. The Ritz method is then applied to derive the eigenvalue
equationwhichcanbesolvedtoobtainthebucklingloadofthebeam.Thebucklingbehaviours
ofthelaminatedbeams,whichincludesurfacestresses,arepresentedanddiscussedindetails.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
207
A0590- THERMAL POSTBUCKLING BEHAVIOURS OF FUNCTIONALLY GRADED
NANOCOMPOSITEPLATES
Y.Fana,H.-S.Shenb,Y.Xiangc
aVisitingResearchFellow,SchoolofComputing,EngineeringandMathematics,Western
SydneyUniversity,e-mail:[email protected]
bProfessor,SchoolofOceanandCivilEngineering,ShanghaiJiaoTongUniversity,e-mail:
cProfessor,SchoolofComputing,EngineeringandMathematics,WesternSydneyUniversity,
e-mail:[email protected]
Thecurrentinvestigationdealswiththethermalpostbucklingbehavioursofnanocomposite
platesconsistingofcarbonnanotubereinforcementsorgraphenesheetreinforcementsunder
a uniform temperature field. The material properties of carbon nanotube reinforced
composite (CNTRC) and graphene reinforced composite (GRC) are both assumed to be
temperature-dependent.TwotypesoffunctionallygradedpatternsfortheCNTRCsingleplate
and the GRC laminated plate are proposed. The plates are assumed to rest on a Pasternak
foundationwithalledgessimplysupportedandin-planeimmovable.TheReddy’sthirdorder
sheardeformableplatetheoryisemployedtoderivethepostbucklingequationswhichalso
include the effects of the von Karman geometric nonlinearity. A two-step perturbation
techniqueisusedtosolvethepostbucklingequationsandaniterationmethodisappliedin
the computation. The influences of the functionally graded patterns and the foundation
stiffness on the thermal postbuckling behaviours of the nanocomposite plates will be
presentedanddiscussedindetails.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0681- Imperfections by Design: Interactive Buckling and Postbuckling in
ArchitectedMaterials
YinghaoZhaoa,b,AmalJeraldJosephMariaJosephc,ChunpingMab,Megan
Skibinskib,BurakGulb,MaryGraceSylvesterc,andNanHub
aDepartmentofCivilEngineering,SouthChinaUniversityofTechnology,China
bDepartmentofCivil,EnvironmentalandGeodeticEngineering,TheOhioStateUniversity,
USA,e-mail:[email protected]
cDepartmentofMechanicalandAerospaceEngineering,TheOhioStateUniversity,USA,
Harnessing elastic instabilities in materials have recently enabled new classes of tunable
systemsanddevices,suchassoftfluidicactuator,metamaterial-basedartificialmuscle,gating
mechanism,origami-inspiredartificialmuscles,nonlinearforcesensor,biomimeticactuators
atarchitecturalscale,andsoftrobotics,etc.Thecommonfeatureofthoseinstability-induced
smartsystemsistheamplifyingforceandaugmentedmotioncomparedtotheirtraditional
stiffcounterparts.Achievingtheseamplifyingeffectsusuallyreliesonharnessingtailorable
architectedmaterials(alsoknownasmechanicalmetamaterials)asthebuildingblock.Oneof
theongoingchallengesishowdefectschangethepropertiesofmechanicalmetamaterialsto
achieve targeted functionalities with aperiodic materials. In response to such need, we
introduce a class of shell structures which undergoes interactive buckling induced by
strategically controlling the number and distribution of geometric defects. By combining
finite-element simulations and desktop-scale experiments, we found that the interactive
bucklingcanbeinducedbystrategicallycontrolledthenumberandthedistributionofdefects,
leadingtoadeterministicactuationresponsecomparedtotheonewithoutgeometricdefects.
Ourstudytherebyopensavenuesforthedesignofthenextgenerationofactuatorsandrobots
withhighfidelityandlowsensitivityoverawiderangeoflengthscales.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
209
A0705-SoilArchingEffectBasedStudyontheStressDistributionandFailureMode
oftheHolesforUnder-excavationinBuildingRectifying
QingxiaYuea,XinZhangb
aSchoolofCivilEngineering,ShandongJianzhuUniversity,Email:[email protected]
bSchoolofCivilEngineering,ShandongJianzhuUniversity,Email:[email protected]
Inthedesignofbuildingrectifyingwithunder-excavationmethod,thedeformationandthe
failuremodeoftheexcavationholesarethekeyproblems.Theywillaffectthedetermination
ofthekeydesignparameterssuchasexcavationdiameterandthedistancesoftheexcavation
holes.Inthisregard,someexperimentswerecarriedouttostudythestressredistribution,
failure mode of the excavation holes. First, a simulation model box was designed with the
ability to simulate the soil excavation. Then the soil excavation was done with the hole
diameter200mm,andthreecaseswithholedistancesof400mm,600mm,and800mmwere
adopted.Thesoilsettlementduetotheexcavationholewasmeasured.Itisfoundthatthere
arethreefailuremodeoftheexcavationholes:verticalirregularoval,horizontalirregularoval,
irregularcircle.Further,itisfoundthatthepressureofthesoilwilltransferfromtheupperof
thehole to thesidesoilbetweentheholes,whichmeanthat thesoilarchingeffectoccurs.
However,duetotheclusterholeseffect,therelativedisplacementissmall.Inthiscontext,the
fullarchingeffectcannotbeformed.Thus,anewcalculationformulaisputforwardwithsome
modifications to the fully arching effect. The calculation results are compared with the
experimental results, which agree well. Furthermore, it is found that as the hole distance
becomes bigger, the soil between the holes will form a steady arching foot, which is
unfavorabletothebuildingrectifying.Thus,itcanbeconcludedthatacriticalholedistance
existbetweensteadyarchingandunsteadyarching.Itcanbeconcludedfromthisexperiment,
2-3timesoftheholediameterisaproperholedistancefortherectifyingdesign.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0776- CLASSIFICATION OF STEEL H-SHAPED CROSS-SECTIONS UNDER
COMBINED COMPRESSION AND BENDING CONSIDERING PLATE INTERACTION
EFFECT
HouXuesonga,ChengXinb
aMiss,CollegeofArchitectureandCivilEngineering,TaiyuanUniversityofTechnology,e-
mail:[email protected]
bAssociateProfessor,CollegeofArchitectureandCivilEngineering,TaiyuanUniversityof
Technology,e-mail:[email protected]
Thecross-sectionclassificationconceptisanimportantpartofsteelstructuraldesign.Inorder
to distinguish the plastic deformation ability of cross-sections, the cross-sections of
compression-bendingmemberscanbedividedintofourclassesaccordingtodifferentplate
width-to-thicknessratiolimits.Howeverbycomparingthewidth-to-thicknessratiolimitsof
thecurrentspecificationsincludingGB50017,Eurocode3,AISC360,AIJ,itispointedoutthat
most of the specifications do not consider the interaction effects of steel plates of cross-
sections.Inthispaper,steelH-sectionswerechosenasthemainresearchobjects.Toconsider
theplateinteractioneffectincross-sectionclassifications,parametricstudyofsteelH-sections
with different width-to-thickness ratios and axial force ratios was carried out by software
ABAQUS. The finite element model was verified by the experimental results in the related
literatures.Throughthesimulationresult itwasobservedthatdifferentwidth-to-thickness
ratiosandaxialforceratioscouldleadtodifferentfailuremodes,bearingcapacityandductility,
sotheinteractioneffectofadjacentplatewasconfirmed.ThenthevaluesofMu/Mecofallthe
finiteelementmodelswereobtained,whereMuistheultimatebendingcapacityandMecisthe
elasticbendingmoment,withinwhichthedominatingparametersoffiniteelementmodels
with Mu/Mec=1 were extracted. Based on these cross-sections with Mu/Mec=1, the fitted
functionfortheclassificationlimitofclass3andclass4cross-sectionsintermsofflangeand
webwidth-to-thicknessratiosandtheaxialforceratioswasproposed.Finally,theproposed
limitationswerecomparedwiththespecificationsincludingGB50017,Eurocode3,AISC360
and AIJ to further prove its correctness, where it is observed that each specification is
relativelyconservativecomparedwith theresultsof thenewlyproposed limitation.This is
mainlybecauseallthespecificationsexceptAIJfollowtheruleofsingleplateconcept,i.e.the
interactioneffectbetweenflangeandwebisignored.Moreover,consideringtheinteraction
effectofadjacentplate ismore in linewiththeactualmechanicalpropertiesofplates,and
wouldleadtocertaineconomicbenefits.
Engineering Mechanics Institute
International Conference 2018 November 2-4 Tongji University
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A0839- FAILURE AND BUCKLING ANALYSES OF COMPOSITE LAMINATES WITH
CUT-OUTS:THEORYANDEXPERIMENTS
JianxiangWanga,ShuLia,HaiDonga,JianlinChena,YanWangb,JifengXub,
ZhengLia
aDepartmentofMechanicsandEngineeringScience,CollegeofEngineering,Peking
University,Beijing100871,China,e-mail:[email protected]
bBeijingAeronauticalScienceandTechnologyResearchInstitute,Beijing100083,China.
Fibre-reinforcedcompositelaminateswithcut-outsmayexhibitcomplexfailuremechanisms
andmodes.Oneofthefailurecriteriaisbasedonacharacteristiclengthattheedgeofthecut-
out.However,thedeterminationofthecharacteristiclengthisalong-standingdifficultissue,
and how it is related to the properties and geometric parameters of the laminate remains
elusive.Moreover,wealsoshowbyexperimentsthatlaminateswithbigcut-outsmayexhibit
localbucklingunderin-planetension.Therefore,first,weshalldiscussthedeterminationof
thecharacteristiclength,andpresentourresultfromaviewpointofnon-localelasticitytheory
of composites. By combining the predicted characteristic length with the improved Puck’s
failuretheory,wedemonstratethatthepredictedstrengthoflaminateswithcircularcut-outs
qualitativelyagreewiththeexperimentalmeasurements.Nevertheless,wealsopointoutthat
therelationbetweenthecharacteristiclengthandthesizeofthecut-outsstilldeservesfurther
investigation.Then,weshowourexperimentalobservationsofthefailuremodesandbuckling
phenomenaoflaminateswithbigcut-outsundertension.Thefailuremodesincludefracture,
splitting, and local buckling. Some laminates may buckle before damage, and the critical
buckling load can be calculated by a power law of the size of the cut-outs. Therefore, the
predictionsofthebehavioroflaminateswithcut-outsshouldbedevelopedtakingintoaccount
differentdeformationandfailuremodes.
Engineering Mechanics Institute
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A0875-BucklingofCompositePlateswithReinforcedOvalHoles
LingweiTanga,YanWangb,MufengDuanc,JifengXud
aEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresandComposite
Materials,e-mail:[email protected]
bEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresandComposite
MaterialsPosition,affiliation,e-mail:[email protected]
cEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresandComposite
Materials,e-mail:[email protected]
dDeputyChiefEngineer,BeijingKeyLaboratoryofCommercialAircraftStructuresand
CompositeMaterials,e-mail:[email protected]
As larger passenger windows are being implemented to increase the comfortableness in
aircraft cabin, stability of composite fuselage panel with cutout becomes a more severe
problem.Reinforcementsadjacenttowindowcutoutmustbeextensivelyevaluatedtokeep
structuralstabilityunderserviceloadsandtooptimizestructuralweightandmanufacturing
costs.Thispaperpresentsexperimentalandnumericalresultsoflaminatedcompositesquare
plates with reinforced oval-like holes. Composite plates with and without window frames
weretestedtoinvestigatetheeffectsofwindowframeonbucklingresponsesubjectedtoshear
loadings.InsteadofconventionalTshapedwindowframe,flatwindowframeswerefabricated
fromdiscontinuousfibercomposite(DFC)usingcompressionmoldingbeforeattachingtothe
laminatecompositeplatebyfasteners.Eliminatingtheperpendicularribbenefitsstructural
weight saving and eases the manufacturing process. In experimental tests structural
deformationanddamageweremonitoredbybothstraingaugesanddigitalimagecorrelation
(DIC)equipment.Numericalanalysiswasconductedusingfiniteelementmethodtosimulate
thebucklingbehaviorof thecompositeplateswithcutouts.Theresults fromexperimental
testsandnumericalanalysiswerecorrelatedwell,andshowthatwindowframesefficiently
preventthecompressiveregionfromlocalbuckling.
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A0925- Strengthening, Failure and Twinning Mechanisms of Graphene/Copper
Composites
NingHua,ShayuanWengbandHuimingNingc
aProfessor,CollegeofAerospaceEngineering,ChongqingUniversity,e-mail:
bDoctoralCandidate,CollegeofAerospaceEngineering,ChongqingUniversity,e-mail:
bAssociateProfessor,CollegeofAerospaceEngineering,ChongqingUniversity,e-mail:
Grainrefinementandintroducingreinforcementshavebeentwocommonandeffectiveways
to improve the strength of metals, where interfaces are found to play a critical role in
mediating the overall mechanical properties of metals based composites. In this study, the
effectsofinterfacesinCu//NiandCu//graphenenanolaminatesonmechanicalpropertiesare
investigatedwithMDsimulations.Itisfoundthatcoherenttwininterfaceshowssignificant
strengtheningeffectsviaplasticdeformationduetothedislocationsinkingeffects.Graphene
reinforcements are then incorporated into Cu matrix, and the underlying strengthening
mechanismofgrapheneandtheeffectoflamellathicknessandfailuremodeareinvestigated.
Incorporatinggraphenemonolayerisprovedtosimultaneouslycontributetothestrengthand
ductilityofthecomposites.Grapheneaffectedzoneisdevelopedandintegratedwithruleof
mixtures and confined layer slip model to describe the elastic properties of NGCu and the
strengtheningeffectoftheincorporatedgraphene.Theanisotropicmechanicalresponsesand
deformation behaviors of graphene/copper nanolaminates under compression are further
explored,dislocationslideandtwiningarefoundtobethedominantdeformationmechanisms
under compression along different crystallographic orientations. A graphene wrinkle
facilitated twinning mechanism are observed and analyzed, which may contribute to the
manufactureofhigh-strengthmetalcompositecombiningthetwinstrengtheningandcarbon
materialstrengtheningeffect.
Engineering Mechanics Institute
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MS18: Computational Modeling of Advanced Materials
and Novel Structural Systems for Hazard Mitigation
A0321- Enhancing Seismic performance of porcelain electrical equipment using
baseisolation
BAIWena,DAIjunwua,YANGYongqianga
aKeyLaboratoryofEarthquakeEngineeringandEngineeringVibration,Instituteof
EngineeringMechanics,ChinaEarthquakeAdministration,Harbin,Heilongjiang,150080,
China
Aseconomydevelops, thesocietyrelies increasingmoreonelectricity.Ensuringthesteady
supply of electricity during natural hazards like earthquakes is of importance. However,
porcelaincylindricalelectricalequipment(PCEE),askeycomponentofpowersupplysystem,
performs badly during earthquakes, which might significantly increase the probability of
poweroutage.InordertoenhancetheseismicperformanceofPCEE,baseisolationisapplied.
Three typical PCEEs with different frequencies, are taken as example and their dynamic
responsesunderearthquakesarestudied.Effectivenessofbaseisolationatdifferentperiods
arecompared.Analysesareconductedusingfiniteelementmethod.Resultsshowthatbase
isolationiseffectivenessatenhancingPCEEseismicperformance.Baseisolationcanreduce
PCEE acceleration and relative displacement responses. The effectiveness of base isolation
increasesasequipmentfrequenciesincrease.Theeffectivenessofbaseisolationincreasesas
base isolation period increases. Meanwhile, it should be noticed that the absolute
displacementresponsesofPCEEmayincreaseasBIperiodincreases.
Engineering Mechanics Institute
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A0360-CharacterizationandModelingofAdaptiveRubberBearing
YiEnJia,C.S.Tsaib,YingZhoucandXilinLud
aMasterStudent,ResearchInstituteofStructuralEngineering&DisasterReduction,College
ofCivilEngineering,TongjiUniversity,Shanghai,e-mail:[email protected]
bDistinguishedProfessor,DepartmentofCivilEngineering,FengChiaUniversity,Taichung,
e-mail:[email protected]
cProfessor,ResearchInstituteofStructuralEngineering&DisasterReduction,Collegeof
CivilEngineering,TongjiUniversity,Shanghai,email:[email protected]
dChenungKongScholarsProfessor,ResearchInstituteofStructuralEngineering&Disaster
Reduction,CollegeofCivilEngineering,TongjiUniversity,Shanghai,email:
Inordertosystematicallyinvestigatethemechanicalbehaviorofanadaptiverubberbearing
(ARB), mathematical formulations for nonlinear analyses have been derived from the
proposed concept of the ARB. Based on the concept of the force equilibrium via the
combination of rubber and the sliding core layer by layer, the mathematical formulations
presentingtheadaptivecharacteristicsoftheentireARBsystemcanbeobtainedbywayofthe
seriesofconnectionsofalllayersintheentiredevice.Byvirtueofthederivedmathematical
formulations,thephenomenaoftheARBisolatorpossessingadaptivefeaturescanbeclearly
understoodeventhoughitisacompletelypassivedevice.Numericalanalysiswhichisingood
agreementwithexperimentalresultsinferthattheeffectivestiffnessanddampingratioofthe
ARB isolator change continually during an earthquake and are controllable through
appropriatedesign.
Engineering Mechanics Institute
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A0363- Multi-Physics Simulation on Passive Patch Antenna Sensor for Wireless
StrainMeasurement
DanLia,YangWanga,b
aSchoolofCivilandEnvironmentalEngineering,GeorgiaInstituteofTechnology
bSchoolofElectricalandComputerEngineering,GeorgiaInstituteofTechnology
Apassivepatchantennasensor isanoveldevice forwirelesslymeasuringstrainonabase
structure.Theelectromagneticresonancefrequencyofthepatchantennaishighlyrelatedto
itsdimension.Whentheantennasensorisdeformedalongwithabasestructureunderstrain,
theresonancefrequencychangecanbeidentifiedwirelesslyandusedtoestimatethestrain.
This research investigates mechanical and electromagnetic behaviors of the patch antenna
sensorbymulti-physicssimulation.A3Dfiniteelementmodelisbuiltforbothmechanicaland
electromagneticsimulation.Inthemechanicalsimulation,nonlinearconstitutiverelationship
ofmaterialisconsideredforcalculatingaccuratedeformationunderloading.Dimensionsof
thedeformedantennamodelarethenusedfortheelectromagneticsimulation,whichadopts
partially air-filled cavity modelling technique for efficiently calculating the resonance
frequency of the patch antenna sensor. The accuracy of this mechanics-electromagnetics
coupledsimulationisvalidatedthroughlaboratoryexperiments.
Engineering Mechanics Institute
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A0368- SECTION AND FINITE ELEMENT ANALYSIS OF SEISMIC UHPC BRIDGE
PIERSWITHHIGHSTRENGTHSTEEL
MohamedA.Moustafaa,NegarNaeimib,MahmoudAboukifab,SureshDhakalb
aAssistantProfessor,DepartmentofcivilandEnvironmentalEngineering,Universityof
Nevada,Reno,email:[email protected]
b Graduate Student Researcher, Department of civil and Environmental Engineering,
UniversityofNevada,Reno
AdvancedbehaviorofUltraHighPerformanceConcrete(UHPC)hasledtoagrowinginterest
amongtheconstructionindustryworldwide.Currently,UHPCisusedwidelyinbridgedeck
joints and connections, and to a less extend in structural components or larger structural
applications.ThestructuralandseismicbehaviorofUHPCforlargercomponentsisnotfully
understood.Moreover,usinghighstrengthsteel(HSS)withUHPCstructuralcomponentscan
openthedoorsfornewdesignopportunities,butyetneedtobestudiedproperlyfordesign
optimizationandobtainedductilityforseismicdesign.Theobjectiveofthispresentationisto
provide better understanding of the seismic behavior and failure mechanism of UHPC
componentswithconventionalandHSSreinforcement(mainlybridgepierscolumnsandbent
caps) due to earthquakes. Two-dimensional sectional analysis using a recently developed
software, MC-BAM, and detailed three-dimensional (3D) finite element modeling (FEM) is
utilized.Forthe3DFEM,thevalidityofTotalStrainCrackmodels,asareadilyimplemented
modelinDIANAFEAsoftware,incapturingUHPCbridgepiersfailuremechanismandplastic
hinge behavior is investigated. The UHPC behavior in tension and compression is
independentlydefinedusinguniaxialstress-strainrelationships,whicharedeterminedusing
extensiveUHPCmaterial tests.TheoverallresponseofUHPCbridgepiersundercombined
axial (gravity) and pushover lateral loads is numerically studied. A reference conventional
reinforced concrete bridge pier column is also presented to study the relative increase in
seismicdisplacementandforcecapacitiesofUHPCbridgepiers.Differentreinforcementratios
alongwithvaryingreinforcementgradesareusedtostudytheeffectoflargerreinforcement
ontheoverallseismicbehaviorofUHPCstructuralcomponents,whichcaneventuallyleadto
newdesignstrategies.
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A0671-SystemLevelAnalytical,ExperimentalandHybridSimulationofResilient
HighwayBridges
YingjieWua,SelimGünayb,KhalidM.Mosalamc
aGraduateStudent,UniversityofCalifornia,Berkeley,e-mail:[email protected]
bProjectScientist,UniversityofCalifornia,Berkeley,e-mail:[email protected]
cTaiseiProfessorofCivilEngineering,UniversityofCalifornia,Berkeley,e-mail:
Thispaperpresents themain featuresandanalytical,experimentalandhybridsimulations
conductedtocharacterizetheseismicperformanceoftwostructuralsubsystemsdesignedand
constructedaroundtheconceptsofResilientStructuresandAcceleratedBridgeConstruction.
Thefirstsystemfocusesonachievingresiliencybyutilizingaclassofinnovativeconnecting
devices,termed“V-connector”.Itcanbeusedtoconnecttwoconstructionpartsinastructural
system, e.g., the column and the bridge deck, or the column and its foundation. The V-
connectoradoptsaspecially-designedV-shapegeometrytoestablishaconnectionthatforms
an isolation layer,whileutilizing its intrinsic friction toachieveenergydissipation,bothof
which are required for seismic resiliency. The resiliency is achieved in terms of the elastic
behavior of the bridge components that would otherwise show inelastic behavior using
conventionaldesign,likethecolumns.Theconnectoritselfisalsosupposedtoremainelastic
during the earthquake. Accelerated Bridge Construction is obtained by assembling pre-
manufacturedstructuralpartsincludingtheV-connectoritselfonsite.Inthesecondsystem,
theconceptofresiliencyisincorporatedintheformofre-centeringbehaviorofthecolumns.
Re-centeringcolumnsaredesignedtoexperienceonlyminordamage locatedat thebeam-
column interface under the same seismic demands that would cause extensive damage in
conventional columns, and to return to their original position after the earthquake by
unbondedpost-tensionedelements.Thisresultsinasignificantreductionintherepaircosts
anddowntime.AcceleratedConstruction isachievedbyutilizingpre-castcolumnsandend
beamsthroughaninnovativesocketconnection.Theworkpresentedhereisanenhancement
andadifferentoutlooktoanearlierresearchconductedonsimilarsystems.
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A0695-StudyontheImpactResistanceCapacityoftheHoneycombSandwichPanel
BasedontheMiuraOrigamiPattern
Ruijun.Maa,Jianguo.Caib,Jian.Fengc
aPhDCandidates,SchoolofCivilEngineering,SoutheastUniversity,Nanjing210096,China.
Email:[email protected]
bProfessor,KeyLaboratoryofC&PCStructuresofMinistryofEducation,NationalPrestress
EngineeringResearchCenter,SoutheastUniversity,Nanjing210096,China.Corresponding
AuthorEmail:[email protected]
cProfessor,NationalPrestressEngineeringResearchCenter,SoutheastUniversity,Nanjing
210096,China.Email:[email protected]
Honeycomb sandwich structures have excellent energy absorption capabilities, combined
with good mechanical properties and low density. These characteristics make them ideal
structuresysteminmanyengineerfields,suchlikecivilengineering,transportationindustry
andaerospaceindustry.Thiskindofstructureisconsistoftopandbottomfacesheetanda
honeycomb core between them. In this paper, a novel honeycomb sandwich panel was
proposed by introducing miura origami pattern as imperfection into regular hexagonal
honeycombcore.Athreedimensionalfiniteelementmodelwithmicro-structureconsidered
of thenovelpanelwasbuilt tovalidatetheenergyabsorptionpropertyunderdrop-weight
impactloadcase.Severalsimulationswithdifferentimpactenergywereconductedandthe
calculationresultsincludingabsorptionenergy,plasticareaandindentationdepthonthetop
face sheet were investigated. The numerical results showed that more than 80% impact
energywasabsorbedbythetopface-sheetandhoneycombcore.Thenovelpanelabsorbed
moreimpactenergyinhoneycombcorethanthetraditionalonedid.Andtheimpactingcaused
larger plastic area on the novel panel. At the second part, the kinematic and geometry
propertiesofmiurapatternwerediscussedtoillustrationtheenergyabsorptionprocessof
thehoneycombcore. Thepanelswithrigid foldablepattern andnon-rigid foldablepattern
werecompared.Inaddition,theeffectofthefoldangleandcorelayeronabsorbingimpact
energywasdiscussedtoproposeadesignmethodofnovelhoneycombpanelwhichwasused
tofindtheoptimalstructureforabsorbingimpactenergy.
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A0729- PRIMARY STRUCTURAL CONFIGURATION INVESTIGATION OF A NOVEL
COUPLINGARMCONNECTINGTWOFLOATINGSTRUCTURES
TaoLia,XudongQianb,AzizMerchantc,AnisHussaind,AmitJaine,BernadA.P.
Francisf,AnkitChoudharyg
aResearchFellow,Keppel-NUSCorporateLaboratory,NationalUniversityofSingapore,e-
mail:[email protected]
bAssociateProfessor,DepartmentofCivilandEnvironmentalEngineering,NationalUniver-
sityofSingapore,e-mail:[email protected]
cResearchEngineer,KeppelTechnology&Innovation,e-mail:
dResearchEngineer,KeppelMarineTechnologyDevelopment,e-mail:
eResearchEngineer,KeppelTechnology&Innovation,e-mail:[email protected]
fResearchEngineer,KeppelDeepwaterTechnologyDevelopment,e-mail:
gResearchEngineer,KeppelTechnology&Innovation,e-mail:
This study reports the primary study on the configuration of a novel coupling arm system
connectingtwofloatingstructuresunderextremewavecondition.Thecouplingarmconsists
of circular hollow section tubes, a pneumatic piston and rotational flexible joints. The
pneumatic piston is designed to absorb the relative surge motion between two floating
structurestopreventpotentialcollision,andtherotationalflexiblejointsareusedforresisting
thebendingloadsduetodifferentrelativemotions.Finiteelementanalysesarecarriedoutto
determinetheinitialnumberoftheflexiblejointsofthecouplingarm.Severalanalysiscases
of thearmconfiguration withdifferentnumbersof the flexible joints are investigated.The
analysiscasesarethencomparedintermsofthereactionforceofthecouplingarmandthe
rotationsoftheflexiblejoints.Finally,theoptimizedstructuralconfigurationforacoupling
armof25.35misrecommended.
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GS1: Stochastic Mechanics and Structural Reliability
A0227-TowardsStochasticModelingofTsunamis
ZhihengWanga,IrinaKTezaurb,PatrickLynetta,RogerGhanema
aSonnyAstaniDepartmentofCivilandEnvironmentalEngineering,UniversityofSouthern
California,210KAPHall,LosAngeles,CA90089,USA,e-mail:[email protected]
bExtremeScaleDataScience&AnalyticsDepartment,SandiaNationalLaboratories,P.O.Box
969,MS9159,Livermore,CA,USA,e-mail:[email protected]
cSonnyAstaniDepartmentofCivilandEnvironmentalEngineering,UniversityofSouthern
California,210KAPHall,LosAngeles,CA90089,USA,e-mail:[email protected]
dSonnyAstaniDepartmentofCivilandEnvironmentalEngineering,UniversityofSouthern
California,210KAPHall,LosAngeles,CA90089,USA,e-mail:[email protected]
Thistalkdescribesaprototypeofanext-generationstochastictsunamimodel,currentlyunder
developmentwithintheparallelandscalableTrilinos-basedAlbanyfiniteelementcodebase.
This emerging model differs from its predecessors in that it is based entirely on the full
nonlinear 3D incompressible Navier-Stokes equations and is amenable to uncertainty
quantification (UQ). The model is expected to accurately represent the nonlinear effects
inherentinthephysicalprocessesunderlyingtsunamis(e.g.,near-shoreevolutionofwaves)
and, when mature, enable probabilistic tsunami hazard analyses. We discuss some
preliminary work towards quantifying the model’s aleatoric uncertainties arising due to
variationsinmodelforcingandgeometry(bathymetry,coastaltopographylanduse)usinga
newadaptivepolynomialchaosexpansion(PCE)algorithmdevelopedwithinUQTk,anon-
intrusivehigh-performancelibraryforUQ.
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A0454- Multidimensional Stochastic Damage Model for Concrete Under Fatigue
Loading
YanpengWanga,JieLib
aPhDStudent,TongjiUniversity,[email protected]
bProfessor,TongjiUniversity,[email protected]
Stayingtheframeworkofclassicalelastoplasticdamagemechanics,anewkindofstochastic
damagemodelthatissuitableformultidimensionalfatigueloadingwasproposedbasedon
theone-dimensionaldamageevolutionlawestablishedbefore.Tobridgethegapbetweenone-
dimensionalandmulti-dimensionaldamageevolution,theconceptofenergyequivalentstrain
isemployed.Toexhibittheapplicationoftheproposedmodel,aseriesofnumericaltestswas
conducted on reinforced concrete beams without web reinforcement, considering the
randomness in constitutive relationship of concrete. Two kinds of failure modes were
identifiedintheresults,i.e.,tensilefatiguefailureofreinforcementandcompressivefatigue
failureofconcrete.Alsoitisdiscoveredthattherandomnessinconcreteispossibletoleadto
changeoffailuremodesofthereinforcedconcretebeamsunderfatigueloading.
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A0554- A Generic Framework For Probabilistic Damage Characterisation Using
UltrasonicGuidedWaveinTheFrequencyDomain
Wang-JiYana*,DimitriosChronopoulosb,SergioCantero-Chinchillac
aInstituteforAerospaceTechnology&TheCompositesGroup,TheUniversityofNottingham,
e-mail:[email protected]
bInstituteforAerospaceTechnology&TheCompositesGroup,TheUniversityofNottingham,
e-mail:[email protected]
cInstituteforAerospaceTechnology&TheCompositesGroup,TheUniversityofNottingham,
e-mail:[email protected]
Ultrasonicguidedwave(GW)whichcanbeactuatedbypiezoelectrictransducersinstalledon
structures has been proven to be sensitive to small and various types of damages. The
reflection/transmissioncoefficientscorrespondingtovariousdamageshasthepotentialtobe
damage-sensitive features in the field of structural health monitoring. This study aims at
formulating a generic framework for probabilistic damage characterization based on
reflection/transmissioncoefficients.Thepresentworkiscomposedoffivecoreelementsthat
makefulluseoftheBayesiansystemidentificationframeworktoaccountformeasurement
noiseandmodelingerrorsintandemwithwaveandfiniteelement(WFE)model:(i)Giventhe
damage model of the structure, the theoretical reflection/transmission coefficients can be
calculatedefficientlyusingWFEmodels.(ii)Theprobabilisticdistributionpropertiesofthe
reflection/transmissioncoefficientsestimatedusingmeasuredultrasonicguidedwavesinthe
frequency domain are inferred based on complex ratio statistics. (iii) Based on the
probabilistic distribution of reflection/transmission coefficients, the likelihood function
connectingthetheoreticalreflection/transmissioncoefficientscontainingtheparametersto
be updated and the measured reflection/transmission coefficients are formulated within a
unified Bayesian system identification framework. (iv) Kriging model that provides a
surrogatemappingbetweentheprobabilityspacesofthedamageparameterstobeidentified
andthetheoreticalreflection/transmissioncoefficientsareemployedtoreplaceasignificant
numberofrelativelytime-consumingWFEsimulationsrequiredinthelikelihoodevaluations
by very fast approximate estimates. (v) The transitional Monte Carlo Markov Chain in
conjunction with the kriging model is used to sample the posterior probability density
functionoftheupdatedparametersataveryreasonablecost.Twonumericalexamplesare
usedtoverifytheaccuracyandefficiencyoftheproposedalgorithm.Resultsindicatethatthe
fast-numerical strategies proposed in this study can improve the computational efficiency
significantly.
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A0639-Anewstochasticfiniteelementmethodforstructuralmodelupdatingbased
onuncertainstaticdata
W.Zhifenga,H.Binb
aPhd,Wuhanuniversityoftechnology,e-mail:[email protected]
bProfessor,Wuhanuniversityoftechnology,e-mail:[email protected]
Thispaperproposedanewstochasticfiniteelementmethodforstructuralmodelupdating
basedonuncertainstaticdata.Basedonthestaticcondensationtechnique,astatisticalmodel
updating equation associated with element updated factors is established. A high-order
perturbationtechniqueisintroducedtoobtainthecoefficientsofthepowerseriesexpansions
of the element updated factors. The Tikhonov regularization and truncated singular value
decompositionareemployedintheprocessofmodelupdatingtosolvethediscreteill-posed
problems caused by measurement noise. The traditional stochastic perturbation model
updating method and Bayesian method based on delayed rejection adaptive Metropolis
algorithmareusedtocomparewiththeproposedmethod,whichcanvalidatethebenefitsof
theproposedmethod.Bothnumericalandexperimentalexamplesillustratetheaccuracyand
efficiencyoftheproposedmethodforfiniteelementmodelupdating.
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A0641-GeneralizedTaylor-seriessolutionofeigenvalueofrandomstructure
H.Zhanga,B.Huangb
aWuhanUniversityofTechnology,Wuhan,China;e-mail:[email protected]
bWuhanUniversityofTechnology,Wuhan,China;e-mail:[email protected]
A new computational method is proposed for solving the eigenvalue of the structure with
randomparametersbasedontherecursivestochasticfiniteelementmethodandgeneralized
Taylor expansion. For this new method, the eigenvalues and eigenvectors of the random
structure are expanded as generalized Taylor-series. The deterministic coefficients in each
term of the generalized Taylor-series are obtained by recursive stochastic finite element
method,thentheapproachingfunctionwithauxiliaryparameterhisaddedineachterm.Due
totheparticipationoftheapproachingfunction,theconvergencedomainofthegeneralized
Taylor-seriesfortheeigenvalueisgreatlyimproved,whichmakesthisnewmethodavailable
forthelargefluctuationofrandomparametersanddifferentfromthetraditionalTaylorseries.
Numericalexampleinvolvingavariablecross-sectioncontinuousbeamindicatesthatthenew
method can provide excellent approximations of the eigenvalues compared with the
perturbationmethodandrecursivestochasticfiniteelementmethod.
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A0751-AFractionalMomentMethodforReliabilityAnalysisofStructuresunderthe
SpatiallyVariability
XufangZhanga,QianLiu
aAssociatedProfessor,SchoolofMechanicalEngineeringandAutomation,Northeastern
University,e-mail:[email protected]
Thereliabilityanalysisofanengineeringsystem,structureorcomponentistypicallybasedon
amodelthatdescribesthesystem'sresponse,suchasdeformation,asafunctionofapplied
loads,operatingenvironment,materialpropertiesandgeometryorconfiguration.Analytical
derivationofthedistributionofafunctionofrandomvariablesisfeasibleonlyinverysimple
cases and it is intractable problem in a general setting. Especially, the spatially varying
uncertaintycannotbehandleddirectlybymeansofstructuralreliabilitymethods.Thepaper
presentsageneralmethodtoderivetheprobabilitydistributionofamultivariatefunctionof
randomvariablesrepresentingtheresponseofastructure.Thederivationisanefforttotackle
the problem via the method of moment. However, a key departure is the use of fractional
momentsoftheresponsefunction,asopposedtointegermomentsusedsofarintheliterature.
Anewmultiplicativedimensionalreductionmethod(M-DRM)isproposedtoapproximatethe
originalcomplexinput-outputrelation.Anefficientnumericalmethodforfractional(integer)
momentcalculationwasfollowedbyusingM-DRMandGaussquadrature.Thesemi-analytical
probability distribution of structural output is determined using the principle maximum
entropy(MaxEnt)withtheconstraintsspecifiedintermsoffractionalmoments.Monte-Carlo
simulation was carried out to assess the accuracy of the proposed methodology. Examples
show that the results of the proposed method are fairly accurate as compared with the
benchmarksbycrudeMonte-Carlosimulation.
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GS2: Computational Mechanics
A0031-COMPUTATIONAPPLICATIONDEVELOPMENTINSCIENTIFICPARADIGM
EchefuFrancisEmekaa
aLecturer,InstituteofManagementandTechnology,[email protected]
The era in computation application development in scientific paradigm has created new
opportunities for researchers to achieve high relevance, impact amid changes and
transformationsinhowwestudybasicsciencephenomena.Withtheemergenceofscientific
paradigmcollectiontechnologies,advanceddataminingandanalyticssupport,thereseemsto
befundamentalchangesthatareoccurringwiththeresearchquestionswecanask,andthe
research methods wecan apply. The contexts include social networks and blogs, political
discourse, corporate announcements, digital journalism, mobile telephony, home
entertainment, online gaming, financial services, online shop-ping, social advertising, and
social commerce.Computing is an evolving technological paradigm that facilitates
conveniently, on-demand network access to a shared pool of configurable computing
resourceslikenetwork,servers,storage,applicationsandservicesetcthatcanbepresented
asaserviceandreleasedwithminimalmanagementeffort.Themodelpromotesavailability
ofresourcesandcreatespowerfuldistributedcomputingsystemwithglobalreachandsuper
computing capabilities. Computing is enriching and will widen the horizon of human
knowledge, empower human capital for sustainable scientific development as well as
educationaldevelopmentofnations.Thispapertriestoexplorethevastandimmensebenefits
of computation development in scientific paradigm shift and its applications in e-library
servicesinAfricatoday.Thiswillallowbusinessanalystsandresearcherstoachievefrequent,
controlled and meaningful observations of real-world phenomena. I discussed how the
philosophyofscienceshouldbechanginginstepwiththetimes,andillustrateourperspective
withcomparisonsbetweenearlierandcurrentresearchinquiryinscientificparadigm.
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A0063-ModelReductionTechniquesforDynamicSystemswithaLargeNumberof
LocalModes
XiaoshuZenga,OlivierEzvanb,BoraGencturkc,RogerGhanemd
aUniversityofSouthernCalifornia,LosAngeles,CA90089,U.S.A.,e-mail:[email protected]
bUniversityofSouthernCalifornia,LosAngeles,CA90089,U.S.A.,e-mail:[email protected]
cUniversityofSouthernCalifornia,LosAngeles,CA90089,U.S.A.,e-mail:[email protected]
dUniversityofSouthernCalifornia,LosAngeles,CA90089,U.S.A.,e-mail:[email protected]
Inacomplexsystemwithbothglobalmodesandmanylocalelasticmodes,thebehaviorofthe
local modes that are well-separated, usually has negligible effect on the global dynamics.
Takingadvantageofthisfact,anautomaticmodeselectionprocedureisfirstproposedtodraw
asubsetofdominantelasticmodesinthefrequencybandofinterestthatcanrepresentthe
global dynamics. This selection procedure is followed by a filtering technique that is
constructed by projecting the responses of the system onto a global displacement basis,
allowingenhancedaccuracyinthehighfrequencyrange.Subsequently,thesetwomethodsare
combinedwithsub-structuringtechniquestoallowforacomputationallyefficientanalysisof
systemswithlargesubstructures.Thetworeductionmethodsareappliedtoahomogeneous
platewith flexibleandstiffparts,asimplifiednuclear fuelassembly,andadetailedboiling
waterreactornuclearfuelassembly.Anotherapplicationofthecanister-fuelassemblymodel
isalsoexaminedtojustifycombiningglobalfilteringwithsubstructuretechniques.
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A0102-GROUP-THEORETICEXPLOITATIONSOFSYMMETRYINCOMPUTATIONAL
MECHANICSOFNOVELPRESTRESSEDSTRUCTURES
YaoChena,JianFengb
aDr.,AssociateProfessor,SchoolofCivilEngineering,SoutheastUniversity,Nanjing,China,e-
mail:[email protected]
bProfessor,SchoolofCivilEngineering,SoutheastUniversity,Nanjing,China,e-mail:
Symmetryisoneofthemostcommonandimportantfeaturesinnature.Differentsymmetry
canbeeasilyobservedfromamicroscopicviewtomacroscopicview,fromatomsandcrystals
to large-scale space structures. At the same time, innovative methods that consider the
inherentsymmetryofasystemwillbesystematicandeffective.Asan importantbranchof
mathematicsandvectoralgebra,grouptheoryisapowerfultoolforsystematicanalysison
symmetricsystems.Ithasbeenextensivelyappliedincomputationalphysics,computational
chemistry,andelectromagnetism.Inrecentyears,grouptheoryhasbeengraduallyadopted
forcomputationalproblemsofsolidandstructuralmechanics.Unfortunately,grouptheory
hasnotbeenwidelyadoptedincomputationalmechanicsofengineeringstructuresbecause
itisabstract(i.e.,mathematicallyrepresented)anduncommontomoststructuralengineers.
In addition, conventional symmetry mentioned in structural mechanics generally refers to
mirror symmetry or cyclic symmetry. This paper introduces the advances made in the
applicationofgrouptheoryincomputationalaspectssuchasstability,form-finding,natural
vibrationandbifurcationanalysisofnovelprestressedstructures.Asinitialprestressplaysan
important role in prestressed structures, its contribution to structural stiffness has been
considered. General group-theoretic approaches for the involved problems are presented,
where certain stiffness matrices and equilibrium matrices are expressed in symmetry-
adaptedcoordinatesystemandblock-diagonalizedneatly.Illustrativeexamplesonstructural
stabilityanalysis,force-findinganalysis,andgeneralizedeigenvalueanalysisoncabledomes
andcable-strutstructuresaredrawnfromrecentstudiesbytheauthors.Itshowshowgroup
theory,throughsymmetryspacesforirreduciblerepresentationsandmatrixdecompositions,
enablesremarkablesimplificationsandreductionsinthecomputationalefforttobeachieved.
More importantly, before any numerical computations are performed, group theory allows
valuable and effective insights on the behavior or intrinsic properties of a prestressed
structuretobegained.
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A0188-EFFECTOFPOWERTAKE-OFFDAMPINGONHYDRODYNAMICEFFICIENCY
OFANOSCILLATINGWATERCOLUMNWAVEENERGYDEVICE
PiyushMohapatraa,AnirbanBhattacharyyabandTrilochanSahooc
aPh.D.Scholar,IndianInstituteofTechnology,e-mail:
Kharagpur,[email protected]
bAssistantProfessor,IndianInstituteofTechnology,e-mail:
Kharagpur,[email protected]
cProfessor,IndianInstituteofTechnologyKharagpur,e-mail:[email protected]
Oneofthesimplestandmostadvancedtechnologiestoharnessenergyfromtheoceanwaves
is the wave energy converter (WEC). A partially submerged semi-closed chamber
encompassesoceanwaterinsidethechamberwithanunderwateropeningtotheocean.Air
is trapped above the free surface inside the chamber. The incident ocean waves excite the
watermassinsidethechamberwhichgoesthroughupanddownmotionwithpassingcrests
andtroughs.Theupwardmovingwatercolumnpushesthetrappedairanddrivesitthrough
anarrowvent.Duringthedownwardmotionofthewatercolumn,alowpressureabovethe
freesurfacedrawsair fromtheatmosphere throughthevent.Apowertake-off(PTO)unit
which in this case is a unidirectional Wells type air turbine is placed in the vent which is
connected to a generator to generate electricity. However, the overall efficiency of these
systems is still not up to the mark for commercial electricity generation. With rapid
advancement in the computational facilities, Computational Fluid Dynamics (CFD) is now
recognizedasanimportantcomplementtotraditionalphysicaltestingtechniquesinocean
engineering. In the present study, numerical investigation of a shore fixed OWC device is
performedusingCFDtoolANSYSFluent.Amultiphasevolumeoffluid(VOF)modelisusedto
design a numerical wave tank (NWT) for simulation of wave generation in an ocean
environment.TheincidentwavescomefromoneendoftheNWTandimpingeontheOWC
chamberplacedontheoppositeendofthetank.Theresultsofwavegenerationarevalidated
with the previous numerical and theoretical results. The flow characteristics inside and
outsideoftheOWCchamberareanalyzed.Thedampingprovidedbytheairturbineismodeled
asflowthroughaporousmedia.Itreplicatesthepressurejump-flowbehaviorofaWells-type
air turbine. Both linear and non-linear models of turbine damping were considered and
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simulations were carried out for different values of porous media parameters to study the
turbine pressure jump characteristics. The hydrodynamic efficiency of the OWC device is
calculated for different values of linear and non-linear turbine damping coefficients. The
hydrodynamic efficiency is plotted against incident wave frequency for various values of
turbinedampingcoefficients.Theresultswerecomparedwiththeresultsfromthepreviously
availableliterature.
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A0211- WEAK ENFORCEMENT OF DISPLACEMENT CONDITIONS IN FICTITIOUS
DOMAINFINITEELEMENTANALYSIS
KaizhouLua,CharlesAugardeb,WilliamCoombsc,ZhendongHud
aPh.D.candidate,TongjiUniversity,e-mail:[email protected]
bProfessor,DurhamUniversity,e-mail:[email protected]
cAssociateprofessor,DurhamUniversity,e-mail:[email protected]
dProfessor,TongjiUniversity,e-mail:[email protected]
In fictitious domain finite element analysis, one of the major difficulties comes from
incorporatingDirichletboundaryconditions,as thegridnodesarenotguaranteed toalign
withthegeometricboundaryofthecomputationdomain.Unliketheclassicalfiniteelement
method,whereDBCscanbeimposednode-wisely,“weak”enforcementmethodsareemployed
asalternatives.InthediscontinuousGalerkinmethod,inwhichadjacentfiniteelementsdonot
have shared nodes, the similar weak enforcement (more often Nitsche’s method) is also
employedtoweaklyattachdisplacementsbetweenelements.Lagrangemultiplier,penaltyand
Nitsche's methods are well-developed approaches in this area that have inspired various
successors, with the recently developed linked-Lagrange multiplier and step boundary
methodsbeingtwoofthem.Herewepresentageneralintroductionofthesetwomethodsand
provide modifications with advantages. A number of numerical examples are provided to
validatetheaccuracyoftheproposedapproaches,withoptimalratesofconvergencehaving
beenachieved.
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A0290- QUANTIFICATION OF ERROR IN COMPUTATIONAL MODELS BASED ON
THREE-DIMENSIONALMICROSTRUCTURECHARACTERIZATION
LoriGraham-Bradya,NoahWadeb
aProfessor,JohnsHopkinsUniversity,e-mail:[email protected]
bStudent,JohnsHopkinsUniversity,e-mail:[email protected]
Three-dimensionalmicrostructurescollectedbyexperimentalcharacterizationprovideboth
statistical information and the basis for computational models, which allows us to analyze
heterogeneous materials at small length scales. However, the collection of such three-
dimensionalmicrostructuraldatacommonlyreliesondestructivetechniques,suchasserial
sectioning,andsuchmethodsoftenprovidenoquantitativemeasureoftheaccuracyofthe
digital microstructure in representing the true physical specimen. This makes quality
assessmentofthedatasetsdifficultanditposesachallengetoidentifywhichcharacterization
parameterswillproduceoptimalefficiencyinthedatacollectionprocesswhilemaintaining
anacceptableleveloferrorintheresultingdata.Toaddressthisquestion,thispresentation
describes a computational method that was developed to simulate serial sectioning data
collection,basedonadigitalrepresentationofamaterial,calledaphantom.Bysimulatingthe
datacollectionanddataprocessingprotocolsofuserdefinedparameterssuchasresolution,
slicethickness,dwelltime,polishingmethod,etc.theeffectofeachonerrorpropagationcan
betrackedrelativetothefullyunderstooddigitalphantom.Thenbyvaryingeachparameter
theeffectscanbestudiedindividuallyandprovideboundsonboththecontributionsofeach
parametertotheerroraswellasthetotalerrorintroducedthroughtheexperimentalprocess.
This provides a quantitative method for comparing the relative trade off between
experimentalparameterssuchcollectingdataataveryhighresolutionvs.collectingdataover
alargevolume.Ultimatelythesemeasuresarethenutilizedaspartofanobjectivefunctionto
optimize the selection of experimental parameters. An example of optimization of
experimental data collection parameters for the acquisition of an 3D Electron Backscatter
Diffraction (EBSD) data set demonstrates how the error in computational models can be
reduced.
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A0629- IMPLEMENTATION OF A MESH SENSITIVE-LESS APPROACH FOR THE
PSEUDO-LOWERBOUNDMETHOD
M.DeFilippoa,J.S.Kuangb
aPhDCandidate,DepartmentofCivilandEnvironmentalEngineering,TheHongKong
UniversityofScienceandTechnology,e-mail:[email protected]
bProfessor,DepartmentofCivilandEnvironmentalEngineering,TheHongKongUniversity
ofScienceandTechnology,e-mail:[email protected]
Intheearlyagesoflastcentury,plasticmethodsofanalysishavebeenintroducedassolution
for applications of the yield-line problem for Reinforced Concrete (RC) slabs. Such field of
researchhasshowngreatpotential for itsapplicationinindustry.Sofar,severalupperand
lowerboundmethodshavebeenproposed,butnoneofthemhaveprovedfullreliabilityyet.
Thecurrentresearchprojectisattemptingtofillthisgapandfocusesonthedevelopmentof
an innovative Pseudo-lower bound method for the assessment of RC slabs. The obtained
results have already reached a good fit with exact analytical solutions for simple cases,
howeverthealgorithmstillhasroomfor improvement. In thispaper, theproblemofmesh
sensitivityisaddressed.Themethodaimsatprovidinganoptimizedlowerboundedsolution,
whichisreachedthroughaniterativeapproachcarriedonwithamonotonicallyincreasing
load.Ayield-checkisperformedateachiterationwithinanincreaseofloadintensity.Theidea
istoassessthestrengthofeachsingleelementindividuallyinanautomatedmanner,hence
creating a localized yield-criterion which is dependent on the mesh size. Through such
improvement, the method would not be dependent on the mesh anymore since moment
capacitiesareadaptedtothesizeofeachsingleelement.Theoutcomeisameshsensitive-less
adaptationofthePseudo-lowerboundmethod,whichremovesitsdependenceonthemesh,
andtendstoincreasetheaccuracyofthesolution,hencepushingthelowerboundfurtherup.
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A0661-MECHANICALPROPERTIESOFFILAMENTOUSNETWORKSINTERMSOF
THEIRMICROSTRUCTURE
HamedHatami-Marbinia
aMechanicaandIndustrialEngineeringDepartment,UniversityofIllinoisatChicago,
Chicago,IL,60607,e-mail:[email protected]
A randomly crosslinked polymer network forms the solid skeleton of many biological
structuressuchasthecytoskeletonandextracellularmatrixofsofttissues.Thecytoskeletal
networkwhichiscomposedofF-actin,microtubules,intermediatefilaments,bindingproteins,
anddifferentcross-linkfilamentsstabilizesthecellmorphologyandmodulatesitsfunction
such as its motility. Similarly, a network of collagen fibers forms the microstructure of the
extracellularmatrixandplaysanimportantroleindefiningthemechanicalpropertiesofsoft
tissues. Thus, it is necessary to investigate the mechanical properties of random fibrous
structures.Inthepresentstudy,wefocusontheroleofthemicrostructureandconnectivity
onthemechanicalpropertiesofthesenetworks.Tothisend,weusedifferentalgorithmsto
construct two- dimensional intertwined fibrous networks. For example, we create two
dimensional fiber network structures by randomly placing fibers of a given length and
orientationinasquaredomain.Rigidconnectionsaredefinedatallpointswherethefibers
cross and the fibers are assumed to have a bending and stretching stiffness. We then use
different non-affinity measure to quantify the mechanical behavior of these networks at
different length scales. We conclude that although the structure and connectivity have
important roles in defining the mechanics of these networks, their effects reduce with
increasingthefibernumberdensityandthebendingstiffnessofthefibers.
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A0700- Analytical Calculation Method for Steel Gate Wide Flange I-Shaped Deep
BeamwithShearEffectofWholeSection
SiyuanWua,ZhengzhongWangb,XuecaiZhangc
aDoctor,StateKeyLaboratoryofDisasterReductioninCivilEngineering,TongjiUniversity,
e-mail:[email protected]
bProfessor,ColdandAridRegionsWaterEngineeringSafetyResearchCenter,Northwest
A&FUniversity,e-mail:[email protected]
cDoctor,ColdandAridRegionsWaterEngineeringSafetyResearchCenter,NorthwestA&F
University,e-mail:[email protected]
Transversalsectioneffectofsheardeformationonbendingnormalstressismoreprominent,
which leading to enormous calculation error used primary beam theory in the traditional
design,becausethefaceplateofhydraulicsteelgatecanbeusedastheflangeofthemainbeam,
andundertheactionofhigh-head,themainbeambearsthenonlinearstresscharacteristics
ofshortdeepbeams.Basedonenergy-variationalmethodwithsheardeformationenergyof
wholeI-beamsection,throughtherationalselectionofthelongitudinaldisplacementfunction
and the warping function, formulas are derived in this paper for the calculation of the
deflection,bendingnormalstressandnaturalfrequency.Onthisbasis,resultsarecompared
with those obtained by various analytical methods and the finite element numerical
simulation results. The results indicate that when span-depth ratio or span-width ratio is
small, the bending normal stress is affected greatly by the transverse shear, and it is more
significant under the concentrated load, but the shear effect reduces it when the natural
frequencyiscalculated.Besides,comparedwiththeexistinganalyticalmethods,theproposed
methodofiersmoreaccurateresultswithanextendedscopeofapplication,whichcanbeused
forthestructuraldesign.
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A0983-AB-SCANSUBSURFACEIMAGINGOFGROUNDCAVITIESUSINGANELASTIC
WAVEFULL-WAVEFORMINVERSIONMETHOD
B.Kima,J.W.Kangb,S.H.Keec,H.Jeongd
aGraduatestudent,Departmentofcivilengineering,Hongikuniversity,
Seoul04066,RepublicofKorea,e-mail:[email protected]
bAssociateprofessor,Departmentofcivilengineering,Hongikuniversity,
Seoul04066,RepublicofKorea,e-mail:[email protected]
cAssistantprofessor,DepartmentofArchitectureEngineering,Dong-AUniversity,
Busan49315,RepublicofKorea,e-mail:[email protected]
dSeniorresearcherengineer,KoreaInfrastructureSafety&TechnologyCorporation,
Jinju52852,RepublicofKorea,e-mail:[email protected]
This paper discusses characterization of ground cavities by an elastic wave full-waveform
inversion(FWI)method.Theelasticwavesaregeneratedbyimpactsontheroadsurfaceand
theresultingsurficialresponsesofthegroundareinvertedforthecharacterizationofroad
cavities.Forthesimulationofelasticwaves,perfectly-matched-layer(PML)isintroducedasa
wave-absorbing boundary, which truncates the semi-infinite domain and removes artificial
reflectionsfromthetruncatedboundaries.TheFWImethodisbasedonapartial-differential-
equation-constrainedoptimizationapproach,whichcanbeimplementedwithKarhsh-Kuhn-
Tuckeroptimalityconditionsforminimizingtheobjectivefunctionalaugmentedbygoverning
elasticwaveequationsviaLagrangemultipliers.Toalleviatetheill-posednessoftheinverse
problem, Tikhonov and total variation regularization schemes are used. To investigate the
feasibility of the FWI method, field experiments were performed on testbed sites with an
artificialcubic-shapedcavityandwitharealroadcavity.Thecavitieshavebeensuccessfully
reconstructedbytheFWImethodusinggroundvelocitiesmeasuredonthepavementsurface.
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GS3: Wood Mechanics
A0308- Development of An Andvanced Fe-Numerical Method for Strength
PredictionofTimberBoardsBasedontheSurfaceInformation
A.KhaloianSarnaghia,J-W.vandeKuilena,b,c
aDepartmentofWoodTechnology,TechnicalUniversityofMunich,80797Munich,Germany
bFacultyofCivilEngineeringandGeosciences,DelftUniversityofTechnology,Delft,
Netherlands
cGuestresearcher,CNR-Ivalsa,Florence,Italy
Full3Dreconstructionofthewoodenlaminationsisaninitialstepinthisstudyforfurther
numericalanalysis.Thisisdonebasedontheknotmeasurementsonthesurfacesoftheboards.
Theaimofthisstudyistodevelopanadvancedvirtualmethodforthestrengthpredictionof
theboards.Byknowingthelocationsoftheknots,asthemainstrengthgoverningparameters
in timber boards, simulations are run for large quality range of wood laminations. This
includes 137 low-medium quality Douglas fir, 103 medium-high quality spruce and some
hardwood boards. The laminations are then used for the numerical analysis of the glulam
composites.ABAQUSandPYTHONareusedforthenumericalsimulations.Anautomaticlink
isprogrammedtoextractthedataofthedatabaseandtocreatethegeometricalmodel.The
3DFE-Analysesofthegeometricallyreconstructedboardsaresuccessfullydoneinthisstudy.
Knotclusters,asmultiplegeometricalimperfectionsintimberboardsarecausinglocallized
highstresses,whichmayleadtotheinitiationofthefailureinthematerial.Therefore,three
mathematicalmethodsarepresentedfromthenumericalsimulationstocalculatethestress
concentration factors (SCFs) around the 3D heterogeneous defects in anisotropic wooden
boards.TheFEMresultsareusedinaregressionanalysistoanalyzethecorrelationswiththe
visualmeasurementsandtopredictthetensilestrength.Basedontheresultsofthemultiple
regressionanalysis,theSCFsaremuchstrongerstrengthpredictorscomparedtotheavailable
visualgradingparameters.Comparingthenumericalpredictionswiththeavailablemachine
gradingmethods,onlytheSCFvaluesaresufficienttopredictthestrengthofthegoodquality
spruce boards, and equally good correlations are found between both results for the low
qualityDouglasfirboards.Usingthedynamicmodulusofelasticityasanadditionalparameter
forthestrengthpredictionsimprovesthequalityofthepredictionssignificantly.Theresults
ofthecurrentstudyshowanimprovementinthestrengthpredictionofwood,basedonthe
numericalsimulationsthataresolelybasedonthegeometricalrepresentationoftheknots.
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A0955-DEFORMATIONKINETICSFORWOODMECHANICS
J.W.G.vandeKuilena,b
aDepartmentofWoodTechnology,TechnicalUniversityofMunich,80797Munich,Germany
bFacultyofCivilEngineeringandGeosciences,DelftUniversityofTechnology,Delft,
Netherlands
DeformationKineticsisbasedonEyringequationsthatdescribetheinfluenceandinteraction
betweenmoleculesand howthese interactionprocessesare influencedbyexternal factors
suchasstressandtemperature.Anumberofresearchprojectshavebeencarriedoutinthe
world using the Eyring´s ground concepts of deformation kinetics. Short and long term
behaviourofwoodcanbedescribedbutitcanalsobeusedasabasistodescribeservicelife
behaviouroftimberstructuresasinfluencedbymechanical,physical,biologicalandchemical
degradationprocesses.Chemicalkineticshasimportantadvantagesoverstandardmicroscale
modelling in that it allows generalizations to multiple planes and scales, whereas
micromechanical modelling is limited to ´perfect wood´, without the influence of grain
deviations,knotsetc.Therefore,microscalemodellingofthemicrostructureofwoodcellsis
generallydescribedwithFEMmodelsorsimilarmodellingtechniquesthatneedsadaptionfor
natural wood failures as knots. Then, Monte-Carlo simulations are needed to account for
spatial variations in material properties. This problem does not occur with deformation
kineticsbecausedifferentreactionratesatthenano-,micro-,andmacrolevelareautomatically
accounted for.Themolecularbehaviour, interactions betweenmoleculesofdifferentorigin
within the wood, vibration behaviour as a function of temperature and last but not least
moisturecannotbeeasilyintegratedinFEMmodels.Applicationofthetheoryleadstovarious
solutionsforcreep,stressrelaxationandbondbreaking,alsoknownasdamageaccumulation.
Thedamageaccumulationtheorycanbeappliedonrealstructures,takingintoaccountcrack
formation,biologicaldegradationandmechanicalloadsatthesametime.Modelpredictions
canbeusedforriskanalysis,residualloadcarryingcapacityestimatesandevenmaintenance
planning.
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A0957- AN INVESTIGATION OF THE DOL EFFECT OF WOOD´IN TENSION
PERPENDICULARTOGRAIN
EnchunZhua
aSchoolofCivilEngineering,HarbinInstituteofTechnology
Wood is a visco-elastic material. Strength of wood decreases under long-term load (DOL
effect).Currently,researchofDOLeffectofwoodintensionperpendiculartograinisnotas
muchasthatofparalleltograin.Inthisstudy,atotalof140NortheastChinalarchsmallclear
specimens were tested under long-term tension perpendicular to grain, in which the
specimenswereclassifiedintothreestresslevels.Theshort-termstrengthofspecimensofthe
matchedsamplewerealsotestedandcomparedwiththelong-termstrength,therelationship
betweenloadingtimeandthestrengthreductionwasthusobtained.Itwasfoundoutthatthe
DOLeffectoftensionperpendiculartograin, followingaconvextrendline,waslesssevere
thanthatpredictedbytheMadisoncurve.Also, thetestresultshowedthatDOLof tension
perpendicular to grain poses little effect on its modulus of elasticity. Four DOL models
includingtheFoschiandYaos’modelwerecalibratedwiththeexperimentaldataandthelong-
term strength was predicted by the calibrated DOL models. Finally, a refined FE model in
considerationofthegrowthringsandcreepofwoodwasdevelopedbasedonANSYS.ViaFE
simulation,thestressre-distributionwasrevealedandthefailuremechanismofwoodunder
long-termloadexplained.
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A0960- AN INVESTIGATION OF FATIGUE FRACTURE OF WOOD DUE TO CYCLIC
MOISTURE_INDUCEDSTRESS
QiongyaoWua,EnchunZhua
aSchoolofCivilEngineering,HarbinInstituteofTechnology
Moisture-inducedstressinwoodwilloccurduetomoisturevariations.Inthisstudy,fracture
of wood due to moisture-induced stress was investigated in a point of view of the fatigue
problem.Fatiguetestsofwoodundercyclicmoisture-inducedstressperpendiculartograin
were conducted on small clear specimens of Scotch pine and Northeast China larch. The
crackingtimeandcrackingphenomenonofthespecimenswereobservedandexplained.AFE
modelwasdevelopedincorporationwithABAQUS,tosimulatethemoisture-inducedstress
inthespecimen.Theconstitutivemodelwasestablishedbyconsideringtheeffectsofthermal
expansion,viscoelasticcreepandmechano-sorptivecreep.ThesimplifiedLuikovheattransfer
modelandFick'ssecondlawofdiffusionwareemployedasthegoverningequationsforthe
heartandmoisturetransfer.TheFEmodelwasusedtosimulatethedistributionofmoisture
contentandmoisture-inducedstressunderdifferentspecimensize,humidityvariationperiod
andamplitude.Moreover,afatiguemodelwasdevelopedbasedontheDVMtheory,andthe
fatiguepredictionbythemodelwascomparedwiththetestresultsofthisstudy.Crackingof
woodduetocyclicmoisture-inducedstresswasthusexplainedfromafatiguepointofview.
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A0968-VARIABILITYINWOOD/PLANTANATOMYALONGTHESCALES
W.F.Garda
aFacultyofCivilEngineeringandGeosciences,DelftUniversityofTechnology,Biobased
StructuresandMaterials,Delft,Netherlands
Plantsarecomplexcompositesofnaturalpolymers.Theydevelopfromlivingmicrocellsto
macro aggregates. Highly lignified plants such as gymnosperms (e.g. softwoods) and
angiosperms (e.g. hardwoods, bamboo) are converted to products which are used among
othersincivilengineeringassolids,fibresandchemicals.Themicroandmacrocomposition
and shape of plants are set by genetic dispositions and reflecting the growth conditions
characterizedbyclimate, soilandexternal loads.Aplant isadynamiccompositestructure
whichreactsandadaptsforexampletowindloads,damagesetc..Thatresultsinamaterial
withaclearlyinhomogeneouscompositestructure.Causedbythenatureofplantgrowth,the
structurehasadistinctorientationoftheplantelementssuchasfibres,vesselsandrays.For
examplevesselsareintendedtotransportwaterfromthesoilviarootsuptotheleavesofthe
plant.Theyareorientedinverticaldirectionasastronglyconnected‘pipenetwork’.Incontrast
raysareorientedhorizontallyandprovidingcellswithwaterandnutrientsinradialdirection.
These composite structures lead to anisotropic behavior of the plant elements. Most
importantplants forcivilengineeringapplicationsaresoftwoods,hardwoodsandbamboo.
The anatomical elements are built up of organic polymers compiled to microfibrils which
progress to cell walls, fibres and finally solid material (e.g. wood, bamboo). The cell wall
consistsofthreemainchemicalcomponents,cellulose,hemicelluloseandligninwithpolymer
dimensions between 10-10 m and 10-9 m. These elements are composed to cell wall layers
whichformsthecellwall(thickness10-6m).Thecellwallcompositedeterminesthephysical
andmechanicalpropertiesofthesinglefibre.Furthermoretheorientationandtheinterface
adhesion between the fibres define the properties of the sound solid material. It has been
demonstratedthatsinglecellulosechainmoleculehasa15timeshighertensilestrengththan
single fibre which is caused by the weak interface actions between layers. However the
complexity of the anatomical elements explains the highly inhomogeneity and anisotropic
behaviorofthewoodandthewidescatterofmechanicalandphysicalpropertieswithinthe
samewoodspeciesevenfromthesameorigin.
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GS4: Structural Mechanics and Simulation
A0164- HYBRID INTELLIGENCE FOR SOLVING COMPLEX ENGINEERING
PROBLEMS:ANINTEGRATEDHUMANANDMACHINELEARNINGAPPROACH
YongmingLiua,YangYub,andHoupuYaoc
aProfessor,SchoolforEngineeringofMatter,Transport&Energy,ArizonaStateUniversity,e-
mail:[email protected]
bPostdoctoralFellow,SchoolforEngineeringofMatter,Transport&Energy,ArizonaState
University,e-mail:[email protected]
cPh.D.candidate,SchoolforEngineeringofMatter,Transport&Energy,ArizonaState
University,e-mail:[email protected]
Thisstudyproposestheconceptofhybridintelligence,aphysics-basedlearningapproachthat
integratesmachinelearningandphysics(humanintelligence),asacomputationallyefficient
methodforsolvingcomplexengineeringproblems.Thephysics-basedlearningencodesthe
underlying physics of engineering problems into machine learning models such as
convolutionalneuralnetworks(CNNs)andrecurrentneuralnetworks(RNNs)toreducethe
trainingandsimulationcosts.Theapplicationofphysics-basedlearningisdemonstratedon
simulatingpartialdifferentialequations(PDEs)andordinarydifferentialequations(ODEs)in
engineeringsystems.Firstly,arecentlyintroducedphysics-awarenetworkknownasthedeep
residual RNN (DR-RNN) is introduced for solving structural dynamic problems. A 10-story
shear building subject to earthquake excitations is used to demonstrate the computational
efficiencyofthephysics-basedlearningapproach.Secondly,weintroduceaFEA-Net,whichis
inspiredbyFiniteElementAnalysis,tosolvethree-dimensional(3D)heattransferproblems
anddemonstrateitsimprovementsindataefficiencyandmemoryconsumption.
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International Conference 2018 November 2-4 Tongji University
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A0259- A PARALLEL SPECTRAL ELEMENT METHOD FOR THE SIMULATION OF
SCALARELASTICWAVES
S.Youna,J.W.Kangb,H.Ryuc
aGraduatestudent,DepartmentofCivilEngineering,HongikUniversity,Seoul,Republicof
Korea,e-mail:[email protected]
bAssociateprofessor,DepartmentofCivilEngineering,HongikUniversity,Seoul,Republicof
Korea,e-mail:[email protected]
cPrincipalResearcher,NationalInstituteofSupercomputingandNetworking,KoreaInstitute
ofScienceandTechnologyInformation,Daejeon,RepublicofKorea,e-mail:
Thispaperdiscussesanexplicitspectralelementmethodforthesimulationofscalarelastic
waves in semi-infinite domains. To simulate the wave propagation in unbounded domains,
perfectlymatchedlayer(PML)isintroducedasawave-absorbingboundarythatsurrounds
thefinitecomputationaldomainofinteresttruncatedfromtheoriginallysemi-infiniteextent.
For numerical implementation of governing scalar wave equations in the PML-truncated
domain,semi-discreteequationsofmotionareconstructedbyusingmixedspectralelements
withtheLegendre-Gauss-Lobattoquadraturemethod,whichenforcesthemassmatrixtobe
effectivelydiagonalized.Thesemi-discreteequationsofmotionaresolvedbythefourth-order
Runge-Kuttamethodfordisplacementandstresses.Thedevelopedspectralelementmethod
has been applied to parallel computing based on message passing interface (MPI), which
demonstrates the feasibility of the proposed method to solving large-scale elastic wave
problems.
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A0267- A NUMERICAL STUDY ON THE THERMO-MECHANICAL RESPONSE OF A
COMPOSITEBEAMEXPOSEDTOFIRE
M.S.Kanga,H.Pakb,J.W.Kangc
aGraduatestudent,DepartmentofCivilEngineering,HongikUniversity,Seoul,
RepublicofKorea,e-mail:[email protected]
bResearchassistant,DepartmentofCivilEngineering,HongikUniversity,Seoul,
RepublicofKorea,e-mail:[email protected]
cAssociateprofessor,DepartmentofCivilEngineering,HongikUniversity,Seoul,Republicof
Korea,e-mail:[email protected]
Thispaperdiscussesananalyticalframeworkforestimatingthethermo-mechanicalbehavior
ofacompositebeamexposedtofire.Theframeworkinvolves:afiresimulationfromwhichthe
evolutionoftemperatureonthestructuresurfaceisobtained;datatransferbyaninterface
model, whereby the surface temperature is assigned to the finite element model of the
structure for thermo-mechanical analysis; and nonlinear thermo-mechanical analysis for
predictingthestructuralresponseunderhightemperatures.Weuseaplastic-damagemodel
forcalculatingtheresponseofconcreteslabs,andproposeamethodtodeterminethestiffness
degradation parameter of the plastic-damage model by a nonlinear regression of concrete
cylinder test data. To validate simulation results, structural fire experiments have been
performedonareal-scalesteelconcretecompositebeamusing the fire loadprescribedby
ASTM E119 standard fire curve. The calculated evolution of deflection at the center of the
beamshowsgoodagreementwithexperimentalresults.Thelocaltestresultsaswellasthe
effective plastic strain distribution and section rotation of the composite beam at elevated
temperatures are also investigated. For fire behavior simulation of the composite beam
protected by fire-resisting materials, the reduction of heat transfer coefficient from the air
layer to the beam is implemented. The series of numerical results demonstrates that the
proposed method of structural fire analysis is suitable for predicting the fire behavior of
compositebeams.
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A0310-TheoreticalStudyOnVibrationOfASimplySupportedFootbridgeUnder
DiscretePedestrianLoading
Shih-HsunYina
aAssociateProfessor,DepartmentofCivilEngineering,NationalTaipeiUniversityof
Technology,Taipei,Taiwan,e-mail:[email protected]
An analytical approach is presented to analyze pedestrian-induced vibration of a simply
supportedbeam.Inthisstudy,discretepedestrianloadingmodelsareproposedtosimulate
each footstep load induced by a pedestrian who walks or runs. The footstep loads act at
differentlocationsalongthebeam,dependingonasteplength.Theloadingtimehistoryofan
individualfootstepisdeterminedbyadifferentforcepulse,dependingonwalkingorrunning.
Based on the analytical approach, relations between the beam response and the pacing
parameters including a pacing period, footstep contact duration, and step length are
theoreticallyinvestigated.Also,theresultsofvibrationestimationofasimplysupportedbeam
underverticalpedestrianloadingshowthattheproposedpedestrian-inducedloadingmodels
aremorereasonablethanthemovingloadmodelusedincurrentfootbridgedesignguidelines.
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A0467- IMPACT LOCATION AND LOAD IDENTIFICATION USING DEEP NEURAL
NETWORKS
JiamingZhoua,LongleiDongb
aXi'anJiaotongUniversity,Xi'an,Shaanxi,710049,P.R.China,e-mail:[email protected]
bXi'anJiaotongUniversity,Xi'an,Shaanxi,710049,P.R.China,e-mail:[email protected]
Identifyingthelocationandhistoryofimpactforceappliedonmechanicalstructuresisvery
important for dynamic design, vibration control, reliability analysis as well as condition
monitoring.Unfortunately,therearemanypracticalsituationswherethedirectmeasurement
ofimpactforcesisnoteasytocarryout,somanyindirectidentificationmethods,includingthe
inverse method, the optimization method, and the neural network method, have been
presentedusingdynamicresponsestypicallymeasuredbyaccelerometersorstraingauges.In
this paper, a new identification method of impact load is proposed based on deep neural
networktechnology.Theloadlocationisdeterminedbyarecurrentneuralnetwork(RNN)
with three-layer long short-term memory (LSTM), and the impact history is evaluated by
three-layerRNNmodelmainlyincludingsingle-layerBLSTM(bidirectionalLSTM)andtwo-
layerLSTM.BLSTMlayerisindispensablebecauseit’shighagreementwiththephysicalreality
ofstructuralvibration.Onlyonemeasuredpoint isused inourresearchandthepredicted
accuracyisnotdependentonthepositionofaccelerometers,whichshowsgreatadvantage
comparedwithothermethods.Besides,somecomplexpreprocessing,likefeaturesextraction,
isnotnecessaryforthismethodandsignaltruncationisappliedforcomputingefficiency.The
impactloadidentificationapproachisqualifiedthroughthesimulatedstudiesforathinplate
structureanddifferentnoiselevelsareconsidered.Inordertocountertheill-posedproblem,
adataaugmentationmethodisadoptedwhichcanidentifytheloadwithhigh-levelnoise.A
GPU-acceleratedlibrary,cuDNN,isusedtotrainthedeeplearningmodelandsearchforthe
optimalhyper-parameters.Theresultsshowthatthelocationandhistoryoftheimpactload
canbeidentifiedaccuratelyusingthepresentedmethod.Thisapproachprovidesaneffective
and feasible way for impact load identification and more engineering structures will be
studiedinthefuture,likelaminatedcompositedplates,complexnonlinearsystems.
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A0512-ULTIMATECAPACITYOFBULGEFORMEDT-JOINTSUNDERBRACEAXIAL
COMPRESSIONEXCLUDINGTHECHORDLENGTHEFFECT
FeilongNiea,QingZhangb,XianrongQinc,YuantaoSund
aSchoolofmechanicalengineering,TongjiUniversity,Shanghai,China,[email protected]
bSchoolofmechanicalengineering,TongjiUniversity,Shanghai,China,[email protected]
cSchoolofmechanicalengineering,TongjiUniversity,Shanghai,China,[email protected]
dSchoolofmechanicalengineering,TongjiUniversity,Shanghai,China,[email protected]
An innovativestiffenedtubular jointcalled thebulge formed jointhasbeendevelopedand
usedinpracticeforthefirsttime.Thoughitsgreatadvantageontheultimatecapacityhad
been proved by authors before, however, no parametric equation was available for the
ultimate capacity prediction. In this study, the finite element (FE) method and a real scale
specimentestwereemployedfortheinvestigationoftheultimatecapacityunderthebrace
axialcompressiveloading,andonlythelengthofjointitselfwasconsideredtoavoidtheoverall
chord length effect. Verified by the test, 27 FE models designed according to the Taguchi
methodologywereusedtoinvestigateeffectsofthegeometricparameters(β,γ,τ,τs,η1,η2)
on the ultimate capacity. Then excluding the parameter η2 whose effect on the ultimate
capacity was found negligible, 324 FE models designed based on the full factorial design
approachwereanalyzedtoderivetheparametricequationfortheultimatecapacity.Byalarge
amountofthenonlinearregressionanalysis,theparametricequationwasderivedwithhigh
accuracy.Theproposedparametricequationcanbeusedfortheultimatecapacityprediction
forthebulgeformedT-jointsunderbraceaxialcompressiveloadingexcludingthechordlength
effect.
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A0595- EXPERIMENTAL ANDNUMERICAL STUDIES OF RESONANCE VIBRATION
OFCABLESINAFOOTBRIDGEMODELUNDERBIHARMONICEXCITATION
W.Pakosa,J.Groselb
aPhD,FacultyofCivilEngineering,WrocławUniversityofScienceandTechnology
WybrzeżeSt.Wyspiańskiego27,50-370Wrocław,Poland,e-mail:
bPhD,FacultyofCivilEngineering,WrocławUniversityofScienceandTechnology,Wybrzeże
St.Wyspiańskiego27,50-370Wrocław,Poland,e-mail:[email protected]
Themethod forreducingresonantvibrationsofstaycables inacablestayedbridgeunder
biharmonicexcitation isdescribed; it isanewmethoddevelopedbytheauthors.Research
results indicate that resonant vibration occurring simultaneously in any two pairs of stay
cablescanbeeffectivelyreducedbychangingstatictensionforcesinappropriatelyselected
stay cables. The selection of cables subjected to the change of static tension forces was
performedonthebasisofsensitivityanalysisofeigenproblemformulatedinaccordancewith
secondordertheoryandoflinearoptimization.Themethodwastestedbothonalaboratory
model of a cable-stayed footbridge and on a numerical (FEM) model of a cable-stayed
footbridgehavinggeometricalandmaterialparametersofarealbridgestructure.Itwasfound
that the change in the cable tension force needed to achieve an effective level of vibration
reductiondoesnotexceedtheUltimateLoadStateorServiceabilityLoadStateoftheobject.
Thisstatementisextremelyimportantasitemphasizesthepossibilityofpracticalapplication
oftheproposedmethodofvibrationreduction.Thegreatadvantageofthevibrationreduction
methoddiscussedhereisthatthereisnoneedtodeterminethecausesofexcessivevibration
associated with excitation. The idea behind the method is to counteract the sources of the
resonancephenomenonbychangingthevalueofthestructure’seigenfrequencyandnotthe
frequencyofexcitation.Theproposedmethodisalsoeffectiveinthecaseoflongcableswhen
passiveandsemi-activevibrationeliminatorsmountedneartheanchoragebecomeineffective.
Theproposedmethodcanserveasanalternativetocommonlyappliedmethodsofvibration
reductionwhichusevibrationdampersandeliminators.
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A0721-non-linearnumericalanalysisonOverallprocessmechanicalbehaviorof
quasi-rectangularsegmentaltunnellining
XianLiua,ZhenLiub,HerbertA.Mangc
aProfessor,CollegeofCivilEngineering,TongjiUniversity,e-mail:[email protected]
bMastercandidate,CollegeofCivilEngineering,TongjiUniversity,e-mail:
cProfessor,InstituteforMechanicsofMaterialsandStructures,ViennaUniversityof
Technology,e-mail:[email protected]
A segmental tunnel lining structure with a novel type of cross-section named quasi-
rectangularisutilizedforthefirsttimeinNingbo,China,asshowninFigure1/a).Thecross-
section is composedof tenblocks(T1,C1,B3,B2,C3,T2,C2,B1,LandF) andan interior
column(LZ).Tenblocksareconnectedbylongitudinaljoints(fromNo.1jointtoNo.10joint).
Three full scale tests have been conducted to investigate the mechanical behavior of the
structure under unexpected circumstance, such as overburden condition, where soil
overburden acts on the top of the tunnel. Based on experimental results of the tests, a
nonlinear finite element method is developed. The model of the structure is composed of
blocks, the interior column, longitudinal joints and a rigid zone. Geometric and material
nonlinearityoftheincludedcomponentsintheelasticandplasticphasesareconsidered.As
showninFigure1/b),theblocksandtheinteriorcolumnaresimulatedbyfiber-integration
beamelements,andthelongitudinaljointsaresimulatedbybeam-springelements.Thecross-
sectionoftheTblockincreasesatitsconnectingparttotheinteriorcolumnanditismuch
stifferthantheneighboringsegment.Therefore,itisidealizedtobearigidzone.Assuch,it
doesnotdeform,butitcanundergoarigidbodydisplacement.Thencomparisonbetweenthe
experimentalandnumericalresultsismade,payingspecialattentiontothefailureprocess,
thedeformationofthelongitudinaljointsandthestrainofthebolts.Theresearchhasshown
that: (1) the non-linear numerical model can accurately simulate the overall mechanical
behavior of the structure and the mechanism of the longitudinal joints, (2) the failure
mechanismofthestructurebeginswithfailureofthelongitudinaljoints.Finally,thestructure
losesbearingcapacity,whichisduetothefactthatshearbearingfailureofTblocksegment
occurs.Accordingtotheanalysisresults,thefailuremechanismofthestructureisdetermined
by the ultimate bearing capacity of the longitudinal joints and the segments, (3) the ideal
failuremodeofthequasi-rectangularsegmentaltunnelliningistoguaranteethatfailureof
the longitudinal joints is earlier than failure of the segment. Therefore, the failure of the
structure is characterized by ductile damage, which results in a high safety reserve of the
structureunderunexpectedcircumstances.
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A0740-VIBRATIONCONTROLBYNONLINEARBOUNDARYABSORBERS
XiaoyeMaoa,HuDingb,Li-QunChenc
aShanghaiInstituteofAppliedMathematicsandMechanics,ShanghaiUniversity,Shanghai
200072,China,e-mail:[email protected]
bShanghaiInstituteofAppliedMathematicsandMechanics,ShanghaiUniversity,Shanghai
200072,China,e-mail:[email protected]
cDepartmentofMechanics,ShanghaiUniversity,Shanghai200444,China,e-mail:
Anonlinearlytorsionalabsorberassembledintheboundaryisproposedforakindofsimply
supported flexible structures. It not only maintains the advantage of the classic nonlinear
absorber,butalsohasacompactstructureandacertainmotionspace.Insimpleterms,the
absorberabsorbsthevibrationenergyviatherotatingangleattheendofthestructure.Then
theenergyisdissipatedbythedamper.Thedampercanbeassembledbetweentheoscillator
andthegroundorbetweentheoscillatorandthestructure.Thefirstoneoffersanonlinear
dampinganddoesn’tappearintheboundarywhilethesecondoneprovidesalineardamping
andappearsintheboundarydirectly.Asaresult,thefirstcasehasnoinfluenceonthelinear
characteroftheoriginalstructure,especiallytheanti-resonance,whilethesecondcasecan
changethem.Butontheotherhand,thesecondcasecanrestrainthevibrationdirectly.The
difficulty for the investigation to these two absorbers is how to deal with the nonlinear
boundaryanalytically.Thedirectmethodofmultiplescales,themethodofmodecorrection
andthemethodofharmonicbalanceareappliedatthesametimetoovercomethisproblem.
Thedifferentialquadratureelementmethodisusedtoverifyanalyticresults.Althoughthe
simulationmethodismoreaccuratethantheanalyticprocess,theanalyticprocedureismore
effective in optimizing the absorber. Based on the investigation, we find that the energy
transmitstotheabsorberalmostunidirectionalandthevibrationofthestructureisdeduced
byalmost90%oftheoriginalresonance.Thenonlinearlytorsionalabsorberintheboundary
providesaneweffectivestrategyforthevibrationcontrol.
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A0903-UnderstandingUncertaintiesfromCyclicTestsofShapeMemoryAlloyBars
forSeismicApplication
JinpengLia,ChengChena,HetaoHoua,CanxingQiua
aJinan250061,ShandongProvince,People’sRepublicofChina,SchoolofCivilEngineering,
ShandongUniversity,e-mail:[email protected]
Shape-memory alloys (SMAs) has the super-elasticity therefore presents promising
application in vibration control of buildings and bridges subjected to seismic loads. The
properties of SMA are often determined through optimization method and treated as
deterministicfordynamicanalysisofstructureswithSMAbaseddevices.Thisstudyutilizes
the Metropolis-Hasting algorithm to characterize the uncertainties in model parameters of
SMA material. The probabilistic characterization presents potential correlations between
model parameters, and offers insight into the uncertainty in SMA behavior under seismic
excitation.AseriesofSMAbarswiththesamegeometricsizeandheattreatmentweretested.
ThebehaviorofSMAbarswerestudiedundercyclic loads.TheMarkovChainMonteCarlo
(MCMC)methodisappliedtoanalyzetheuncertaintiesofSMAintermsofmodelparameters,
equivalentdamping,andrecenteringcapability.
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International Conference 2018 November 2-4 Tongji University
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GS5: Bio-Mechanics and Bone Mechanics
A0667-THERELATIONOFCORNEALHYDRATIONANDSTIFFNESSIMPROVEMENT
BECUASEOFTHECORNEALCROSSLINKINGTREATMENT
HamedHatami-Marbinia,SandeepJayarama
aMechanicaandIndustrialEngineeringDepartment,UniversityofIllinoisatChicago,Chicago,
IL,60607,e-mail:[email protected]
Corneaisatransparenttissuethatisnecessaryforprovidingclearvisionandshieldingthe
intraocularcomponentsof theeye fromexternaldamage.Keratoconus isacornealdisease
whichaltersthemicrostructuralorganizationofthecollagenfibrilsandsubsequentlydamage
the structural integrity of the tissue. The loss of corneal structural integrity results in its
progressivethinningandassumingaconicalshapebecauseoftheintraocularpressure.The
cornealcollagencrosslinkingisatreatmentproceduretohalttheprogressionofthedisease.
Inthisprocedure,collagencrosslinksareintroducedinsidethestormainordertostrengthen
the mechanical properties of the corneal tissue. The commonly used collagen crosslinking
procedureiscomposedofsoakingthetissueintheriboflavinsolutionandthenexposingthe
tissuetoUVAirradiation.TheUVAraysdamagetheendothelialcells if thethicknessofthe
corneais lessthan400microns.Thus, it issuggestedtosoakthecorneasinhypoosomolar
solution(whichcausesexcessivecornealswelling)inordertotreatpatientswiththincorneas.
Despitethesuccessofthisalternativecrosslinkingprocedure,itisnotyetknownhowitwill
affect its strengthening effects if an isoosmolar solution is used. In the present study, the
porcine corneas were swollen to different thickness levels before crosslinking. Crosslinked
corneaswerethenbiomechanicallytestedtocharacterizetheirtensilestrengthusingaDMA
machine. The amount of stiffening due to the collagen crosslinking treatment was fully
characterizedasa functionof their initialhydration. Itwasobservedthat theextentof the
stiffeningofthecrosslinkingtreatmentwasindependentofthehydrationlevelatwhichthe
corneal samples were crosslinked when the tensile measurement was done at normal
hydration levels. The experimental observations were explained by a mathematical model.
ThefindingsofthepresentstudyfurthersupportedtheideaofusingthemodifiedUVcorneal
crosslinkingintreatingpatientswiththinkeratoconiccorneas.
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A0870-A3-DimensionalModellingComparisonof theBiomechanicalStabilityof
LateralLumbarInterbodyFusionwithUnilateralorBilateralFixationMethod
TengZhanga,SiweiBaib,ChrisFanga,Tak-ManWonga,JasonCheunga,WilliamLua,Ashish
Diwanc
aDepartmentofOrthopaedicsandTraumatology,QueenMarryHospital,TheUniversityof
HongKong,HongKong,e-mail:[email protected];
bDepartmentofElectricalandComputerEngineering,TechnicalUniversityofMunich,
Munich,Germany,e-mail:[email protected]
cSpineService,StGeorgeHospital,Sydney,Australia,e-mail:[email protected]
In treating recalcitrant low pain or spinal deformity using interbody fusion, unilateral and
bilateralfixationmethodshaddemonstratedsimilarclinicalefficacy.Finite-elementanalysis
oflumbarbiomechanicsisperformedinthisstudytoinvestigatetheunderlyingmechanisms
ofunilateralversusbilateralfixation.TheanonymisedCTscansofahumanlumbarspinefour
and five (L4 and L5) were acquired at the Department of Orthopaedics and Traumatology,
QueenMarryHospital,theUniversityofHongKong,withanisotropicspatialresolutionof1
mm.ThesegmentationoftheCTscanswasperformedin3DSlicer,anopen-sourceplatform
formedicalimageprocessing,whichresultedinsurfacetriangularmeshesofthetwolumbar
vertebrae L4 and L5, as well as their major spinal stability structures, i.e. the anterior
longitudinalligamentandfacetjoints.Acylinderwithalengthof45mmandadiameterof5.5
mmwasbuiltasanidealizedshapeofthepediclescrewimplant.Thescrewswereinserted
intothelumbarvertebraeatthesamepositionssimulatingthesurgery,andconnectedbya
third cylinder representing the rod with a radius of 5.5mm. An interbodycage, created in
SolidWorks, was later placed between the bodies of the two vertebrae. Subsequently, all
surfacemeshes(Figure1)wereconvertedinGeomagicStudio(3DSystems,NC,USA)intonon-
uniformrationalbasisspline(NURBS)surfacepatchesthroughaseriesofmanualprocedures.
ThesurfacemodelswereimportedtoCOMSOLMultiphysics(COMSOLAB,Sweden),across-
platformfinite-element(FE)solver,fortheanalysisofthestressconditionwithbothunilateral
andbilateralfixationmethods.
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The 5th EMI International Conference 2019
Wearepleasedtoinviteyoutothe5thEMIInternationalConference2019,inLyon,France.
ThetopicsoftheconferencearerelatedtoCivilandMechanicalEngineeringfieldswithan
interest on cross- and/or multi-disciplinary fields such as Material and Environmental
Sciences,ITandBigDataanalysis,SocialimpactofNaturalHazardsetc.
ThisConferencewillprovideauniqueopportunityforinternationalresearchersandindustry
experts to discuss recent results and developments in their fields of interest for mutual
benefits. Approaches combining experiments, modeling and/or simulations including the
influence of the boundary conditions (in situ experiments or simulations) and fabrication
processareverywelcome.
WithanveryefficienttransportationsystemandeasilyconnectedfromForeigncolleagues,
the City of Gastronomy is rich in historical and cultural attractions, INSA Lyon is looking
forwardtowelcomingyou!
AliDAOUADJI, on behalf of the organizing team.
What are the topics?
AsfortheannualEMIconferences,theEMIICLyon2019staysinlinewithitslong-standing
tradition as the prime venue for disseminating the most recent progress in Engineering
Mechanics as the core discipline of science-enabled Civil Engineering and Mechanical
Engineering as well. Mutual benefit are coming from cross and multi-disciplinary fields
combining
Conference venue
LyonTechLaDouaCampusandINSALyon’sfacilitieswillwelcomeyouduringyourstay.There
are numerous hotels downtown in Lyon located in very beautiful neighbourhoods and in
Villeurbannetoo.
GoodaccesstotheairportsofLyonSaint-ExupéryandParis-CharlesdeGaulleandParis-Orly,
aswellastothecentralstationusinghighspeedtrainsTGV,isprovided.TaketheTramways
T1orT4andyouwillreachtheCampus.
Engineering Mechanics Institute
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Who are the organizers?
EMI International Conference is organized under the auspices of Engineering Mechanics
Institute(EMI)whichisaDepartmentoftheAmericanSocietyofCivilEngineers(ASCE).The
LocalandInternationalScientificCommitteesaregivenintheWebsite
(emilyon2019.sciencesconf.org)
We’ll keep you informed.
All informationconcerningtheconferencevenue, lodging,registration, fees,mini-symposia
andabstractsubmissionandtheprogramwillbeprovidedsoonontheconferencewebsite
emilyon2019.sciencesconf.org.Feelfreetopassthisannouncementtoanyonewhomightbe
interested.
See you in Lyon next July!
Dates&deadlines
15September2018Mini-Symposiumsubmissionopens
1October2018Conferenceregistrationopens
1December2018Abstractsubmissionopens
28February2019Abstractsubmissioncloses
1April2019Notificationtoauthorsonacceptance
2July2019Arrival®istration,Icebreakerevening
3-5July2019EMIInternationalConferenceLyon
Engineering Mechanics Institute
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JoinEMIToday
November 2th, Friday
14:00--21:30 Registration (The 3rd floor of Kingswell Hotel VIP Room)
19:00--21:00 Ice Breaker Reception
November 3th, Saturday
8:00--18:00 Registration (Sino-French Center Room C201)
8:30--8:50 Welcoming Remarks
8:50--9:00 Group Photo
9:00--10:20 Plenary Lectures
9:00--9:40
Prof. Zdeněk P. Bažant
Lecture title: Design of New Materials and Structures to Maximize Strength at Probability
Tail: A Neglected Challenge for Quasibrittle and Biomimetic Materials
9:40--10:20Prof. Hai-Yan Hu
Lecture title: Engineering Dynamics of Soft Machines
10:20--10:40 Coffee Break
10:40--12:10 Technical sessions
12:20--13:30 Lunch
14:00--14:40 Plenary Lecture
Prof. Jin-Guang Teng
Lecture title: Mechanics of interfaces in FRP-strengthened structures
14:50--15:50 Technical sessions
15:50--16:10 Coffee Break
16:10--17:55 Technical sessions
18:30--21:00 Banquet
November 4th, Sunday
8:30--9:50 Plenary Lectures
8:30--9:10Prof. Herbert Mang
Lecture title: Multiscale Analysis of Concrete StructuresA Joint Research Project of Tongji University and Vienna University of Technology
9:10--9:50Prof. Lori Graham-Brady
Lecture title: Uncertainty propagation from materials characterization to modeling
9:50--10:10 Coffee Break
10:10--12:10 Technical sessions
12:20--13:30 Lunch
14:00--14:40 Plenary Lecture
Prof. Jiun-Shyan (JS) Chen Lecture title: Meshfree Methods: Progress Made After 20 Years and Future Directions
14:50--16:05 Technical sessions
16:05--16:25 Coffee Brea
16:25--18:10 Technical sessions
Program At A Glance