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LARGE COMPOSITE SPACE STRUCTURES: FAILURE ANALYSIS AND EXPERIMENT
Vibration Suppression – Precision Motion Control
Emmett Nelson, Firehole Technologies
Adam Biskner, CSA Engineering
Presented to:
AIAA Rocky Mountain SectionAIAA Rocky Mountain Section
January 29th, 2009
1
STRU
CStructural Failure Test Program
AFRL Static Test Facility• AFRL is directing an investigation to d th bilit f it
CTURA
LFA
advance the capability of composite failure analysis from the coupon level to full‐scale structures
• Testing conducted by CSA Engineering in th AFRL St ti T t F ilit
AILU
RETEST
the AFRL Static Test Facility
• Firehole Technologies provided analysis using Helius:MCT
• Tested three previously flight qualified EDU t t t f il
TPRO
GRA
M
EDU structures to failure • CASPAR MPA (Minotaur IV), Atlas V ISA,
and Delta IV PAF
• Compared to failure predictions from conventional FE models and advanced FE
Conic ISA
MPA
M
conventional FE models and advanced FE models to test data
• Evaluating the validity of the design by comparing the structural capacity to the flight conditions
CASPAR
g
• Scaled worst case qualification load profiles and increased applied load until structural failure was achieved• CASPAR and ISA experienced a “flight
Delta IV 1780 PAF
Vibration Suppression – Precision Motion Control
• CASPAR and ISA experienced a flight‐like” composite failure
2
Pump
LOADC
Hydraulic Service Manifold (HSM)
Distribution Manifold (S V l )
CONTRO
LA
(Servo Valves)
Actuator
ANDDATA
A
Load Cell
Load
ACQ
UISITIOLoad
Controller
UPS
LVDT
ON
Data Acquisition System
Vibration Suppression – Precision Motion Control
System
3
INTEG
RA• Agilent® data acquisition system
• 256‐channel front‐end ATED
INST
• Fully integrated with the load controller with MTS software
• All channels recorded at 1% load intervals or as required RU
MEN
TAT
intervals, or as required
• Sensors • Typical test includes only strain and
displacement TION
displacement• Able to condition anything with a voltage output
• Full bridge strain gage based deflection t d i f 0 25” t 5”transducers, ranging from 0.25” to 5”
• Digital video recorded during loading operations
Vibration Suppression – Precision Motion Control
4
• Load control parameters are t d
TEST
OActuator Control Profile
custom programmed per experiment
• Parameters are redundantly reviewed by QA engineer
PERATIO
N
reviewed by QA engineer
• All channels are controlled simultaneously in accordance with a load profilewith a load profile
• Concurrently subjected to 9 limit and error detectors
• Live data displayed during testPl d i l i l di i
250H ld P i
Live Data Comparison
• Plotted against analytical predictions
• Test can be paused or aborted at any time per engineering request 150
200PredictionGauge 1Gauge 2
Hold Points
0
50
100
0 20 40 60 80 100 120 140
Vibration Suppression – Precision Motion Control
0 20 40 60 80 100 120 140Percent of Flight Load
5
WHOIS
• Composite Adapter for Shared PAyload Rides
• Multi‐payload adapter (MPA) for Minotaur IV CASPA
R?
Vehicle • Utilizes excess Peacekeeper missile motors to provide low‐
cost LEO launches (~$20 mil.)
• Nominal payload capability of 4000 lbm
• Designed to integrate two primary spacecrafts (1000‐2000 lbm) per Minotaur launch• Different design approach than previous MPA’s
• Composite material minimizes payload mass penalty• IM7/8552 unidirectional tape• 2 Identical monocoque shells • 60 inches tall, 74 inches in diameter• Integrated composite flangesIntegrated composite flanges • 62.01” diameter bolt pattern
• One primary stowed, other placed atop adapter• Requires Latching Lightband (LLB) low shock separation
d l d b l S C i
Vibration Suppression – Precision Motion Control
systems, developed by Planetary Systems Corporation• Bonded only joint between LLB/CASPAR
6
CASP• Test designed to drive failure in the transitional radius between the conic
section and the aft flange
PAR T
ESTD
section and the aft flange
• Shear, moment, and axial load combination balanced to maximize aft compression while preventing failure in other critical regions
M i t FWD H d t < 3X li it
DESIG
N
• Max compression at FWD Hg adapter < 3X limit
• Max tension at lightband < 4X limit
• Maximize aft CASPAR flange compression
opposite access doors (270o)
Critical Aft Flange (Failure Region) Line LoadCritical Separation System Line LoadCritical Forward Adapter Line LoadLine Load (lbs/in) Line Load (lbs/in) Line Load (lbs/in)
Max Compression at Limit -252 Max Tension at Limit 114 Max Compression at Limit -252Max Applied Compression -755 Max Applied Tension 440 Max Applied Compression -1421
Predicted Failure -1000
Percent above Limit 564%
Vibration Suppression – Precision Motion Control
M.S. at Max Applied Load 0.00 M.S. at Max Applied Load 0.03 Percent above Predicted Failure 142%
7
CASPA
R
A t t L d (lb )*
• Two axial actuators apply pure compression (no bending)
• Lateral actuator applies moment
Test Stack
Applied Loads R TEST
Lateral AXI090 AXI27035760 -20250 -20250
Actuator Loads (lbs)*
*A positive load indicates a tensile actuator load
and shear
• Axial actuators biased to offload the weight of the load head and Hg adapter
• 100% represents flight line load used to
100 kip Axial Actuators
100% represents flight line load used to design the structure
• Failure test includes:• 50% and 100% checkout run
% f fl d
900
44 kip
Lateral Actuator
Load Head
• 250% Aft flange strain demonstration
• 884% failure run
Failure Test Profile
400
500
600
700
800
900
Lim
it Lo
ad
Primary LoadsCounter Balance
Actuator
Peak t i
Forward Hg Adapter
0
100
200
300
400
0 200 400 600 800 1000 1200 1400
% o
f L stress in aft flange 180° from the door
Failure Test Setup
Vibration Suppression – Precision Motion Control
Load Step Failure Test Setup
8
ATLA
SV
What is This Beast?• Atlas V CCB Conical ISA
Test Design• Test designed to drive failure in the top
f th d
V CONICIS
• On all Atlas V 400 series launches
• 12.5 foot diameter to 10 foot diameter, 65 inches tall cone
• Demonstration unit for lightweight
corner of the door • Failure mode suggested by ULA analysts
• First load case applied to as‐built ISA
• Failure load represents 200% of the A ANDTES
g gtooling development program
• Graphite/epoxy and honeycomb mandrel
• Typical composite tooling made from Invar• Long lead times and expensive
pgreatest FWD Flange Peq in ULA test plan
• Limited by the actuator capacities
• Second door installed since original door section did not fail ST
DESIG
N
Long lead times and expensive
• Heavy and difficult to work with
• Currently manufactured in Spain• Creates schedule and cost issues for ULA
C t d i d it b l t
section did not fail• 180o opposite original door, eliminating
pad up around door
• Door section cutout using original ATK tooling , process, and technician• Component redesign render unit obsolete
at the end of a 5 year, $6 million effort
g , p ,
• Second load case same as the first, applied max compression over new door
Vibration Suppression – Precision Motion Control
9
ISA T
• Test stack modified from Qualification Configuration
• Forward stiffness simulator removedR d
Qualification Test SetupTEST• Aft LOx tank simulator removed
• Center actuator biased to offload the weight of the load head
• Failure test includes:
Removed
• Failure test includes:
• 40% and 100% checkout run
• 200% failure run
• As‐built structure successfully withstood 200%
Removedy
load condition
• Second door installed
• Second case conducted by reversing the direction of the applied loads
Failure Test Setup
180%
200%
direction of the applied loads
Load Profile
20%
40%
60%
80%
100%
120%
140%
160%
% of Failure Load Primary Loads
Counter Balance
Vibration Suppression – Precision Motion Control
0%
0 100 200 300 400 500 600 700 800
Load Step
10
FAILU
• Produce a composite failure in the test article
• Record critical strain and displacement data at each load step RETEST
O
• Record critical strain and displacement data at each load step
• Acquire adequate load, strain, and displacement data such that quantitative assessment of the load bearing capacity of O
BJECTIVES,
the structures can be made and to allow comparison to pre‐test analytical models
• Identify resulting initial and final failure mechanism , AKA
SUCC
• Identify resulting initial and final failure mechanism
• Assemble test results, conclusions, and disseminate to community CESS
CRITEERIA
Vibration Suppression – Precision Motion Control
11
ANALY
Real World Failure Exercise• Provide blind failure predictions of large composite structures YSIS
OBJEC
• Provide blind failure predictions of large composite structures
• Predict initial failure, progression, and final failure
• Transfer new technology to the commercial analysis community CTIVES
• Model entire structure with a single detailed model
• Reasonable time frame (weeks)
• Why Firehole: Under the direction of AFRL, Firehole Technologies has been developing an advanced composites analysis technology for several years. The Structural Failure Test program was an great y p g gopportunity to validate the software, or learn where improvement was needed.
Vibration Suppression – Precision Motion Control
12
COMP
Firehole Technologies
• Firehole was founded in 2000 PANYOVER
• Our mission is to deliver tools and services that enable wide‐spread application of composite materials leading to lighter, stronger, safer and more fuel efficient structures RVIEW• Two distinct business areas:
Software DevelopmentStructural Analysis
• Firehole is a profitable, employee owned company focused on delivering more accurate results and a higher degree of confidence in
Software DevelopmentStructural Analysis
Vibration Suppression – Precision Motion Control
delivering more accurate results and a higher degree of confidence in composite simulations
13
FIREH
Current Products Upcoming ProductsHOLESOFTW
• Online, searchable database of composite material datasheets for material selection and comparison
• Cyclic loading simulation• Currently in Alpha• Development partnerships with a large W
ARE
SOL
material selection and comparison Development partnerships with a large Helicopter OEM and a major Naval contractor
LUTIO
NS
• Multiscale composites progressive failure technology • Layerwise Finite Element technology
• Simple transition between 2‐D (Shell) and ( l d) l h3‐D (Solid) Elements using the same
element/model
• Online, micromechanics based composite material simulator
• Composite simulation package for sustainable industries (Wind Turbine Blades Hydrogen Fuel Cells Lighter
Vibration Suppression – Precision Motion Control
14
Blades, Hydrogen Fuel Cells, Lighter Automobiles)
HELIUU
S:MCT
Helius:MCT™ is an enhancement to commercial finite element packages specifically for efficiently improving the accuracy of composite structures analysesanalyses.
• Uses fiber and matrix stresses to predict failure
• Extremely efficient
d d l• Standard material inputs
• Easy to adopt
• Always converges
• Proven results
Vibration Suppression – Precision Motion Control
15
CASPA
• First attempt at the CASPAR analysisAR: BLIN
DP
Model Details• Continuum shell elements PRED
ICTION
• 60 + plies through thickness (1 element)
• 15,000 elements• Handbook material N
SHandbook material characterization
• Fixed constraints at boundary• Continuous run time: overnight
l l d• Entire analysis completed in < 2 weeks
• Initial matrix failure: 1269% FLL%• Initial fiber failure: 1944% FLL
Vibration Suppression – Precision Motion Control
16
CASPACASPAR was successfully tested to ultimate
failure on April 14, 2008 AR: F
AILU
R
% FLL Failure Event
234 I iti l t i ki
RETEST
234 Initial matrix cracking sounds
319‐469 Occasional matrix cracking noisenoise
470 + Continuous matrix cracking noise
500 L b d i500 Lap band gapping
644 Door debond
792 Lower radius failure
847 Ultimate failure
Vibration Suppression – Precision Motion Control
17
CASP
Model Improvements
• 3D layer solid elements PAR : LESS
• 4 elements through thickness
• General mesh refinement
• Contact and nodal ties at Load Head(steel) O
NLEA
RN
Contact and nodal ties at bolt locations
Code Improvements
Test Adapter(7075 T7451 Alum.)1560 elements
(steel)54 elements
Forward Adapter(IM7/8552)
58600 elements EDCode Improvements
• Convergence algorithm improved
1560 elements
Access Doublers(IM7/8552)
558 elements each
Lightband(7075 T7451 Alum.)
464 elements
58600 elements
Aft Adapter
Model Details
• 122,146 elements
Aft Adapter(IM7/8552)
58600 elements
Base Plate(steel)1696 elements
• Continuous run time ~1½ days
• 8 node desktop p.c.
18
UPD
A
% FLL F il E t
Fiber FailureMatrix FailureNo Failure
ATED
ANALY
% FLL Failure Event
260 Initial matrix failure 520 % FLLFailure State
Fiber FailureMatrix FailureNo Failure
YSISRESU
L
261‐480 Matrix failure progression
500 + Rapid matrix failure
LTS500 + Rapid matrix failure progression
740 First fiber failure 800 % FLLFailure State
Fiber FailureMatrix FailureNo Failure800 Fiber failure in lower
radius
980 Ultimate Failure13001450
(discontinuity in load vsdisplacement)
840 % FLL
Vibration Suppression – Precision Motion Control
19
UPD
A3ATED
ANALY
2
2.5
in)
Potential ultimate failure
YTICALLO
A1.5
2
Displacem
ent (
ADVS
DISP1
Compressive DPLA
CEMEN
T
0.5
T
0
0 200 400 600 800 1000 1200 1400 1600
Flight Load (%)
Vibration Suppression – Precision Motion Control
20
Flight Load (%)
CASPPA
R: FAILULower Radius Failure
Ultimate Failure
Helius:MCT Ultimate Failure
URE
EVEN
TDoor Debonding
Helius:MCT Initial Fiber Failure
COMPA
RIS
Lapband Gapping
Helius:MCT Initial Matrix Failure
SONInitial Matrix Cracking
Occasional Matrix C ki N i
Continuous Matrix C ki N iCracking Noise Cracking Noise
Vibration Suppression – Precision Motion Control
21
STRA
INCOMPA
RRISON
IV13153
IV33151IM22701OV33151
IM12701
IV73151OV73151
IM12701
Vibration Suppression – Precision Motion Control
22
3 CASP
980
2
2.5
in)
PAR F
AILU
740
T U
ltim
ate:
9
mat
e: 8
47
1.5
2
Displacem
ent (
REPRED
ICT260
s:M
CT
Fibe
r:
Hel
ius:
MC
ASPA
R U
ltim
1
Compressive D TIO
NCOM
MC
T M
atrix
: 2
Hel
ius
: 110
0
r: 13
00
mat
e: 1
950?
CA
0.5
PARISO
NHel
ius:
M
ashi
n M
atrix
:
Has
hin
Fibe
r
Has
hin
Ulti
m
0
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Flight Load (%)
H
Vibration Suppression – Precision Motion Control
Flight Load (%)
23
REA
SOONSFO
RD
First analytical discontinuity in global stiffness occurs 15% higher than actual ultimate failure.
DIFFEREN
CE
• Model does not capture lapband gapping
• Model does not capture door debonding
• Material disorganization occurring at flange radii not captured
ES• Material disorganization occurring at flange radii not captured
• Possibly reduce residual stiffness (ongoing work)
• Difficult to determine where ultimate failure occurs
24
ISA A
• ISA AnalysisANALYSIS
Model details• 3D model of entire structure• 3D layered solid elements M lti l l t th h thi k• Multiple elements through thickness
• Coupon material characterization• Model generation ~ 2 weeks • 192,000 elements
Load Head‐1440 solid, linear, reduced‐integration elements (Abaqus:C3D8R)
Forward Adapter/Splice‐2902 C3D8R elements
,• Continuous run time ~1 ½ days
• 8 node desktop p.c.
Composite Conic‐186,152 solid, linear, reduced‐integration, composite elements (Abaqus:C3D8RC3)‐These elements have one integration point per ply
Aft Adapter/Splice‐1518 C3D8R elements
Vibration Suppression – Precision Motion Control
25
ISA A
ISA As Built Helius:MCT Failure PredictionsASBUILT
HELIU
S:MCFailure of Structure
340% FL
Limit of Load Frame200% FL
T FAILU
RE
340% FL
PRED
ICTIOONS
Vibration Suppression – Precision Motion Control
26
ISA A
ISA As Built Test ResultsASBUILT
TE
The ISA was successfully tested to 200% FL on October 3, 2008.
•The structure responded nearly linearly to the loading.k bl
ESTRESU
LT
•Testing was remarkably quiet.
TS
1500
-1000
-500
00 50 100 150 200
DOOR233EMIN
800
1000
1200
14000 50 100 150 200
DOOR233EMAX
-3500
-3000
-2500
-2000
-1500
µStr
ain
% Flight Load
0
200
400
600
800
µStr
ain
% Flight Load
Vibration Suppression – Precision Motion Control
Experimental Data Firehole Technologies' Predicitons Experimental Data Firehole Technologies' Predicitons
27
MODI
ModificationsIFICA
TIONS
A second access door was cut into the ISA
l d
S
•180° opposite original door•No pad up around new door•Original ATK tooling was used•Honeycomb edge potted as original
•Loads were reversed
Vibration Suppression – Precision Motion Control
28
HELIU
Helius:MCT Predictions of Modified ISAUS:M
CT PRRED
ICTIONS
Initial fiber failure180% FL
SOFM
ODUltimate Failure
Initial matrix failure110% FL
IFIEDISA
187% FL
Vibration Suppression – Precision Motion Control
29
HELIU
Helius:MCT Predictions of Modified ISAUS:M
CT PRRED
ICTIONSSOFM
OD
186.72 % Flight Load 187.52 % Flight Load
IFIEDISA
Vibration Suppression – Precision Motion Control
187.68 % Flight Load
30
VIDEO
• VideoO
Vibration Suppression – Precision Motion Control
31
FAILU
Failure Test
The modified ISA was successfully tested to failure on October 24 2008 RETEST
The modified ISA was successfully tested to failure on October 24, 2008.
• 183% Flight Load
• Linear response
• Instantaneous event
• Door corners
Failure initiated at door corners
Rapidly propagated around circumference
Vibration Suppression – Precision Motion Control
32
ISA F
ISA FailureAILU
RE
Close up of upper door corner
Failure occurred on interior face sheets
Vibration Suppression – Precision Motion Control
33
RESU
LResults: Interior Strain Gauge
2000
ess
LTS: INTERI
1500
train
Tsai
-Wu
Max
Str e
IORSTRA
IN
1000
Prin
cipa
l St
nt CT
Hash
in
NGAUGE
500Max
P
Expe
rimen
Heliu
s:M
C
00 50 100 150 200 250 300 350 400
E
Vibration Suppression – Precision Motion Control
% Load
34
CONC
• Structural Failure Test Program Successful
• Two large space structures were tested to failure
CLUSIO
NS
• Two large space structures were tested to failure.
• Analytical results within 15% of ultimate failure on CASPAR
• Analytical blind predictions with 2.5% of ultimate failure on ISA
• Traditional composites analysis technologies over predict failure by a minimum of 1.5.
“I had anticipated that most large aerospace composite structures were considerably over‐designed, and this program proved that on all structures tested With innovative analysis technologies such as Helius:MCT fromtested. With innovative analysis technologies such as Helius:MCT from Firehole Technologies, I am convinced that these composite structures could remove as much as 40% mass, which translates into tremendous savings for many space applications.” g y p pp
Dr. Jeffry Welsh
Program Director
Chief Tier 3 Division ORS Office
Vibration Suppression – Precision Motion Control
Chief, Tier‐3 Division, ORS Office
35
Yellowstone Park’s Firehole River
BACKUP
COMP
Composites Failure TechnologiesPO
SITESFA
Conventional technologies treat composites like “black aluminum”
• Mask interactions
l l
ILURE
TECH
• Failure single event
• Unusable degradation models
• Exotic material parameters HNOLO
GIES
• Computationally unfeasible
Action in composites occurs in the Fibers OR the Matrix SAction in composites occurs in the Fibers OR the Matrix
Vibration Suppression – Precision Motion Control
37
TRA
DI
T i Hill
• Tsai‐Wu • Extension of Tsai‐Hill or
H ff t l t
ITIONALC
O
• Tsai‐Hill• Extension of von Mises to
orthotropic materials.
Hoffman to a general stress state.
• Invariant under coordinate rotation O
MPO
SITE
• Hoffman• Extension of Tsai‐Hill for
differing tensile and
• Use of tensors make mathematical operations easy
• Biaxial data required to determine failure parameters F
AILU
REC
compressive properties
• Simple to use in design
determine failure parameters.
• Hashin• Differentiates between fiber
d t i f il
CRITERIA
and matrix failure
• Distinguishes between tensile and compressive modes
All of these criteria are applied to a homogeneous composite and neglect the interaction between the fiber and matrix
38
MULT
Multicontinuum Theory (MCT)TICO
NTIN
UU
MCT decomposes composite stress into fiber and matrix stress• Based on Hill (1963)• Development @ Univ of Wyoming since 1988 U
MTHEO
R
Development @ Univ. of Wyoming since 1988
Accurately represent material phenomena
RY(M
CT)MCTMCT
Composite Stress
Vibration Suppression – Precision Motion Control
Fiber and Matrix Stress
39
COMP
Composite Under Mechanical LoadingPO
SITEUNDComposite Stress: DER
MECH
Fiber Stress:
σ11f = 108 Ksi
σ22f = ‐205 Ksi
σ11 = 0
σ22 = ‐200 Ksi
σ33 = ‐200 Ksi ANICA
LLO
σ22f 205 Ksi
σ33f = ‐205 Ksi
OADING
Matrix Stress:
σ = 143 Ksiσ11m = ‐143 Ksi
σ22m = ‐192 Ksi
σ33fm= ‐ 192 Ksi3
Vibration Suppression – Precision Motion Control
1 2
40
en1
Slide 40
en1 Update lamina pictureemmett_nelson, 12/15/2008
COMP
Composite Under Thermal LoadingPO
SITEUNDComposite Stress: Fib St
DER
THERM
Composite Stress:
σ11 = 0
σ22 = 0
σ33 = 0
Fiber Stress:
σ11f = ‐44.5 (MPa)
σ22f = ‐17.25 (MPa)
σ33f = ‐17.25 (MPa) MALLO
ADI
σ33f 17.25 (MPa)
NG
Matrix Stress:
σ11m = 66.75 (MPa)
σ = 25 87(Pa)
ΔT = ‐216 °C
σ22m = 25.87(Pa)
σ33fm= 25.87 (Pa)
3
Vibration Suppression – Precision Motion Control
1 2
41
PRO
GProgressive Failure Analysis
RESSIVEFA
matrixmatrix fiberfiber AILU
REANA
matrixmatrixfailurefailure
fiberfiberfailurefailure
ALYSIS
Material State 1Material State 1undamaged matrix,undamaged matrix,
Material State 2Material State 2failed matrix,failed matrix,
Material State 3Material State 3failed matrixfailed matrixundamaged matrix,undamaged matrix,
undamaged fibersundamaged fibersfailed matrix,failed matrix,undamaged fibersundamaged fibers
failed matrix,failed matrix,failed fibersfailed fibers
σc matrix failure eventmatrix failure event
11fiber failure eventfiber failure event
Vibration Suppression – Precision Motion Control
22 3342
en2
Slide 42
en2 Color Codeemmett_nelson, 12/15/2008
FINITE
Finite Element ImplementationEELEM
ENTTIM
PLEME= N
TATIO
N
=1 element 11148 elements
Using MCT, a one element model gives the same averaged fiber and matrix stress as a micromechanics model
Vibration Suppression – Precision Motion Control
43