Topology optimisation : a case studyFenci, GE, Currie, NGR and Hardie, G

http://dx.doi.org/10.2749/222137817821232450

Title Topology optimisation : a case study

Authors Fenci, GE, Currie, NGR and Hardie, G

Publication title IABSE Conference Bath 2017: Creativity and Collaboration

Publisher International Association for Bridge and Structural Engineering

Type Conference or Workshop Item

USIR URL This version is available at: http://usir.salford.ac.uk/id/eprint/42742/

Published Date 2017

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IABSEConference–CreativityandCollaborationApril19-202017,Bath,UnitedKingdom

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Topologyoptimisation:acasestudy

GiuliaEvelinaFenci,NeilG.R.CurrieUniversityofSalford,Salford,UK

GregHardieArup,Manchester,UK

Contact:g.e.fenci@edu.salford.ac.uk

Abstract

Parametricandcomputationaldesignplayamajorroleincontemporaryarchitectureandengineering.Designersneednolongerconformtopredeterminedshapesandsections,butaregivenfreedomtoexplorenewgeometriesandstructuralforms.Anexampleofhowanorganicprocesscanbeemployedtofindingthesolutiontoadesignproblemispresented.Topologyoptimizationisstudiedtosuggestdifferentalternativesforthecreationofanopenandfunctionalinternaltowerstructureinaneducationalbuilding.

Keywords:topologyoptimisation;structuraloptimisation;parametricgeometry;naturalstructures;biomimetics;lightweightstructures.

1 IntroductionTopology optimisation is based on determiningthe optimum distribution of material within adesign region. The constraint parameters are theapplied loads, the support conditions, theoverallvolumeofthestructureandsomepossibledesignrestrictions such as the position and size ofprescribedholesandsolidareas[1].

Frei Otto [2] was a pioneer in linking naturalforms to structural design, observing how innature many structures conform to lightweightprinciples combiningminimummaterial use withmaximumstrengthandstability.Naturecanserveas a source of inspiration, however, directimitation will likely yield invalid results. A recentstudy comparing nature’s growth processes andtopologyoptimisationwasconductedbyLochner-Aldinger, Karl and Adriaenssens [3]. The authorspropose a classification of biomimetic structuralsystemscombinedwithusingoptimisation, tryingtorecreatethestructureofbonesanddiatomsvia

topology optimisation. The study deals withstructuralbehaviouronlyanddoesnotattempttounequivocally imitate nature; rather anabstraction process is carried out to transfernaturalprinciplestostructuraldesign.

2 MethodologyA topologyoptimisationprocesswasadopted forthe generation of an alternative proposal for apotential tower in the central space of aneducational building. The structurewas intendedto support tiered seating and a crane to liftexhibits to the ceiling. As the university buildingwas designed to host all engineering disciplines,thearchitect’sproposalsuggestedagatewaythatreflected and enthused the concept ofengineering. The proposed design conveyed thismessagethrougharationaltrussstructure.

Theprojectengineerswerekeentoinvestigateanalternative way of representing their disciplinethroughanorganicengineeringmethodology.Thisfocused on utilising contemporary engineering

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technology and separating it from commonengineeringstereotypes.

Today, with advanced manufacturing processes,optimisation techniques can be applied to findother ways of meeting the necessaryrequirements, freeing the design from therestrictions of standard topologies and offeringmoreefficientsolutions.

Differentscenarioswithvaryingsupportsandloadcases were studied, each producing a uniqueoutcomeoncethetopologyoptimisationwasrun.Thiswas carried out in Grasshopper[4] using the2D analysis of the Millipede plug-in[5]. Thesupporting structure of the event space wasrepresented by a 2D plate with in plane forces.Theanalysiswas thenbasedonarasterisationofthe domain producing a grid of square plateelements on which the topology optimization iscarriedout.

Figure1.Onetopologyoptimisationsolution.

3 DiscussionThe resemblance to dendriforms is apparent,however,theprinciplebehindthedesignissimilarto that of bone growth, rather than treelikestructures. Bones are formed via adaptivemineralisationandbuildupwheremorepressure

is applied and reduce their mass where notrequired, limiting the bone’s overall weightwithoutcompromisingthestructure[6].Similarly,theresultsofthetopologyoptimisationproducedmorphologies that traced the direction the loadfollowed to reach the support locations, creatingstrikingandsuggestivescenariosthatbestconveywhat contemporary structural engineering iscapable of by combining the imitation of naturewiththeadoptionofoptimisationtechniques.

4 ConclusionThis research project was aimed at investigatinganalysis tools for an alternative proposal for thedesign of an internal tower that would illustratethepotentialcomputationaldesignhasbroughttotheworld of engineering. The study shows howdesigners have greater freedom to exploredifferent forms and solutions as the tools tocreatemoreorganic structures arenowavailablewere previously only more regular and highlyorderedstructureswerepossible.

5 AcknowledgementsThisresearchwasinitiatedandsupportedbyArupinManchester.

6 References[1] M.P.Bendsoe,andO.Sigmund,Topology

optimization: theory, methods, andapplications: Springer Science & BusinessMedia,2013.

[2] F. Otto, Natürliche Konstruktionen:DeutscheVerlags-Anstalt,1982.

[3] I. Lochner-Aldinger, J. Karl, and S.Adriaenssens, "Biomimetic approach tostructuralmorphology."

[4] D. Rutten, "Grasshopper: generativemodelingforRhino(Computersoftware),"2007.

[5] M.Panagiotis,andK.Sawako,"Millipede,"2014.

[6] G. Pohl, and W. Nachtigall, Biomimeticsfor Architecture & Design: Nature-Analogies-Technology:Springer,2015.