R223ABAQUS资料IABSWK05QSeal.docx

R223ABAQUS资料IABSWK05QSeal.docx

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R223ABAQUS资料IABSWK05QSeal

Note:

ThisworkshopprovidesinstructionsintermsoftheAbaqusKeywordsinterface.IfyouwishtousetheAbaqusGUIinterfaceinstead,pleaseseethe“Interactive”versionoftheseinstructions.

PleasecompleteeithertheKeywordsorInteractiveversionofthisworkshop.

Goals

∙Evaluateahyperelasticmaterial.

∙Definecontactinteractionsusingcontactpairsandgeneralcontact.

∙PerformalargedisplacementanalysiswithAbaqus/Standard.

∙UseAbaqus/Viewertocreateacompressionload-deflectioncurve.

Introduction

Inthisworkshop,acompressionanalysisofarubbersealisperformedtodeterminetheseal’sperformance.Thegoalistodeterminetheseal’scompressionload-deflection（CLD）curve,deformationandstresses.TheanalysiswillbeperformedusingAbaqus/Standard.Twoanalysesareperformed:

oneusingcontactpairsandtheotherusinggeneralcontact.

AsshowninFigureW5–1,thetopoutersurfaceofthesealiscoveredwithapolymerlayer,andthesealiscompressedbetweentworigidsurfaces（theupperoneisdisplacedalongthenegative2-direction;theloweroneisfixed）.Duringcompression,thecovercontactsthetoprigidsurface;theoutersurfaceofthesealisincontactwiththecoverandthebottomrigidsurface;inadditiontheinnersurfaceofthesealmaycomeintocontactwithitself.

FigureW5–1.Sealmodel

Sealanalysis

1.Changetothe../abaqus_solvers/keywords/sealdirectory.

2.Opentheinputfilew_seal.inp,whichalreadycontainsthenodes,elements,andmaterialmodeldatafortheanalysis.YouwillfirstuseAbaqus/CAEfunctionalitytoevaluatethestabilityofthehyperelasticmaterialmodelandthenedittheinputfiletoincludethecontact,stepandboundaryconditiondefinitions.

MaterialEvaluation

Itisimportanttodeterminewhetherthematerialmodelofthesealwillbestableduringtheanalysis.Beforecompletingtheinputfile,evaluatethematerialdefinitionthatisusedfortheseal.

1.Useyourtexteditortoreviewthesuppliedworkshopmodelcontainedinthefilew_seal.inp.

2.ThematerialnamedSANTOPRENEisusedfortheseal.Locatethe*MATERIAL,NAME=SANTOPRENEoption.Itisahyperelasticmaterialwithafirstorderpolynomialstrainenergypotential.Thecoefficientsarealreadyspecifiedfortheanalysis.

3.Evaluatethematerialdefinition.Abaqus/CAEprovidesaconvenientEvaluateoptionthatallowsyoutoviewthebehaviorpredictedbyahyperelasticmaterialbyperformingstandardteststochooseasuitablematerialformulation.YouwillusethisoptiontoviewthebehaviorpredictedbythematerialSANTOPRENE.

a.StartasessionofAQUS/CAEusingthefollowingcommandatthecommandprompt:

abaquscae

IntheStartSessiondialogbox,underneathCreateModelDatabase,clickWithStandard/ExplicitModel.

b.IntheModelTree,double-clicktheMaterialscontainertocreateamaterialdefinitionasspecifiedintheinputfile.IntheEditMaterialdialogbox,namethematerialSantoprene;fromthemenubar,selectMechanical→Elasticity→Hyperelastic;intheHyperelasticfield,selectthePolynomialstrainenergypotentialandtheCoefficientsinputsource,acceptastrainenergypotentialorderof1,andenterthevaluesofthecoefficients（definedintheinputfile）asshowninFigureW5–2.ClickOKtosavethematerialdefinitionandexitthematerialeditor.

FigureW5–2.Materialeditor

c.FromthemainmenubarinthePropertymodule,selectMaterial→Evaluate→Santoprene.

d.TheEvaluateMaterialdialogboxappears.NoticethatyoucanchooseeithertheCoefficientsorTestdatasourceforevaluatingthematerial.Typicallythetestdataareusedtodefineamaterialmodel;youcanusetheEvaluateoptiontoviewthepredictedbehaviorandadjustthematerialdefinitionasnecessary.Inthisworkshopyouwillonlyevaluatethestabilityofthematerialmodelforthegivencoefficients.

e.

IntheEvaluateMaterialdialogbox,acceptalldefaultsandclickOK.Abaqus/CAEcreatesandsubmitsajobtoperformthestandardtestsusingthematerialSantoprene;atthesametime,Abaqus/CAEswitchestotheVisualizationmoduleanddisplaystheevaluationresultswhenthejobiscomplete.FigureW5–3showstheMaterialParametersandStabilityLimitInformationdialogbox;FigureW5–4showsthreestressvs.strainplotsfromuniaxial,biaxial,andplanartests.

QuestionW5–1:

Whatdotheplotsindicateaboutthestabilityofthematerial?

Basedontheseresults,youcanhaveconfidencethatyourmaterialwillremainstable.

FigureW5–3.Materialparametersandstabilitylimitinformation

FigureW5–4.Materialevaluationresultsforuniaxial,biaxial,andplanartests

Afterevaluatingthematerial,youcanexitAbaqus/CAEandwillnowcompletethemodeldefinition.

Part1:

Analysisusingcontactpairs

Contactinteractions

4.Opentheinputfilew_seal.inpinatexteditor.

5.DefinecontactpairsaslistedinTableW5–1.ThesurfaceswhichwillbeusedinthecontactpairdefinitionsareshowninFigureW5–5.Therequiredoptionis:

*CONTACTPAIR,INTERACTION=frictionless,TYPE=SURFACETOSURFACE

sealOuter,bottom

sealOuter,cover

cover,top

Notethattheinteractionpropertynamedfrictionlesshasalreadybeendefinedintheinputfile.Locatethe*SURFACEINTERACTION,NAME=frictionlessoptiontoreviewitsdefinition.

TableW5–1.Contactpairs

SlaveSurface

MasterSurface

sealOuter

bottom

sealOuter

cover

cover

top

FigureW5–5.Contactsurfaces

6.Defineaself-contactdefinitionfortheinnersurfaceoftheseal:

*CONTACTPAIR,INTERACTION=frictionless,TYPE=SURFACETOSURFACE

sealInner,

QuestionW5–2:

Intheinteractionbetweenthesealandthecover,whydowechooseSealOuterastheslavesurface?

Stepdefinition

7.Defineageneralstaticstepconsideringgeometricnonlinearity.Usestaticstabilizationandsettheinitialtimeincrementsizeto0.5%ofthetotaltimeperiod.Invoketheunsymmetricsolver（theunsymmetricsolverisgenerallyrecommendedforthesurface-to-surfacecontactdiscretizationmethod）:

*STEP,NLGEOM=YES,UNSYMM=YES

*STATIC,STABILIZE=1.e-6,ALLSDTOL=0

0.005,1.

8.Usethefollowingsolutioncontrolparametertoimprovetheefficiencyoftheanalysis:

*CONTROLS,ANALYSIS=DISCONTINUOUS

Boundaryconditionsandhistoryoutputrequests

9.AsymmetriclateralslidingofthemodelispreventedbyconstrainingthesealandthecoveralongtheirverticalsymmetryaxesintheX-direction.Thebottomrigidsurfaceisfixed,andadisplacementof–6unitsisappliedtothetoprigidsurfacealongtheY-directiontocompressthesealbetweenthetwosurfaces.ThenodesetsonwhichtheboundaryconditionswillbedefinedareshowninFigureW5–6.Thefollowingoptioncompletestheseboundaryconditions:

*BOUNDARY

fix1,1,1

botRP,ENCASTRE

topRP,1,1

topRP,2,2,-6.

topRP,6,6

FigureW5–6.Nodesets

10.ThepreselecteddefaultfieldoutputdoesnotincludethenominalstrainNE;tovisualizethenominalstraininAbaqus/Viewer,youwillwriteadditionalfieldoutputtotheoutputdatabasefile.Locatethe

*OUTPUT,FIELD,VARIABLE=PRESELECToptionandadd

thefollowingsub-option:

*ELEMENTOUTPUT

NE,

11.AddahistoryoutputrequesttowritethehistoryofRF2andU2forthesettopRPtotheoutputdatabasefile.Therequiredoptionis:

*OUTPUT,HISTORY

*NODEOUTPUT,NSET=topRP

RF2,U2

12.Saveallthechangesandclosetheinputfile.

Runningthejobandvisualizingtheresults:

Runtheanalysisusingthefollowingcommand:

abaqusjob=w_seal

Whenthejobiscomplete,usethefollowingproceduretovisualizetheresultsusingAbaqus/Viewer:

13.StartAbaqus/Viewerandopenthefilew_seal.odb:

abaqusviewerodb=w_seal.odb

14.Plottheundeformedandthedeformedmodelshapes.Todistinguishbetweenthedifferentparts,colorcodethemodelbasedonsectionassignments.

Tip:

Fromthetoolbar,selectSectionsfromthecolor-codingpulldownmenu,asshowninFigureW5–7（orusetheColorCodeDialogtool

tocustomizethecolorforeachsection）.

FigureW5–7.Color-codingpulldownmenu

15.UsetheAnimate:

TimeHistorytool

toanimatethedeformationhistory.

16.Displayonlytheseal.IntheResultsTree,expandtheInstancescontainerunderneaththeoutputdatabasefilenamedseal.odb.Clickmousebutton3ontheinstanceSEAL-1andselectReplacefromthemenuthatappears.

Abaqus/CAEnowdisplaysonlytheelementsassociatedwiththeseal.

17.ContourtheMisesstressofthesealonthedeformedshape.Ifnecessary,usetheframeselector

inthecontextbartoselectthelastincrement.

ThecontourplotisshowninFigureW5–8.

FigureW5–8.Misescontourplot

18.Contourtheminimumandmaximumprincipalnominalstrains.Elasticstrainscanbeveryhighforhyperelasticmaterials.Becauseofthis,thelinearelasticmaterialmodelisnotusedbecauseitisnotappropriateforelasticstrainsgreaterthanapproximately5%.

19.Displaythereactionforcehistoryatthereferencenodeofthetoprigidsurface:

IntheResultsTree,expandtheHistoryOutputcontainerunderneaththeoutputdatabasefilenamedw_seal.odbanddouble-clickReactionforce:

RF2PI:

TOP-1Node3inNSETTOPRPtodisplaythereactionforcehistoryatthereferencenodeofthetoprigidsurface.

20.YouwillnowcreatetheCLDcurve.

f.IntheHistoryOutputcontainer,clickmousebutton3onReactionforce:

RF2PI:

TOP-1Node3inNSETTOPRPandselectSaveAsfromthemenuthatappears.SavethedataasForce.

g.Clickmousebutton3onSpatialdisplacement:

U2PI:

TOP-1Node3inNSETTOPRPandselectSaveAsfromthemenuthatappears.SavethedataasDisp.

h.IntheResultsTree,double-clickXYData.IntheCreateXYDatadialogbox,selectOperateonXYdataasthesourceand