ppt1、接触CONT-L02-Workflow

Thefollowingtopicsarecoveredinthislesson.Lessoncontent:ContactWorkflowWorkshopPreliminariesWorkshop1:CompressionofaRubberSeal(IA)Workshop1:CompressionofaRubberSeal(KW),Lesson2:ContactWorkflow,90minutes,Bothinteractive(IA)andkeywords(KW)versionsoftheworkshopareprovided.Completeonlyone.,ContactWorkflow,DefiningContactPairsDefiningSurfacesforContactPairsDefiningGeneralContact,DefiningContactPairs(1/12),Featuresofcontactpairs:Contactbetweenpairsofsurfacesisexplicitlydefined.TheuserdefinesWhatconstituteseachsurface.Whichpairsofsurfaceswillinteract.Whichsurfaceisthemaster,andwhichistheslave.Whichsurfaceinteractionpropertiesarerelevant(e.g.,friction)Thecontactpairalgorithmhascertainrestrictionsonthetypesofsurfacesinvolved.Discussedlater.Theinputrequiresmoreworkonthepartoftheuserthangeneralcontact.MustdefinesurfacesInteractionsaredefinedonapair-wisebasis,DefiningContactPairs(2/12),Example:AnalysisofajouncebumperAjouncebumperisahighlycompressiblecomponentthatisusedaspartoftheshockisolationsysteminavehicle.Theanalysisconsistsoftwosteps:Step-1Interferencefitbetweenthebumperandtheshaft.Step-2Movethebottomplateuptocompressthebumper.Thebumperisexpectedtofoldasitiscompressed,soself-contactmustbedefined.Considerfirstusingcontactpairs.,DefiningContactPairs(3/12),Example(contd):Definesurfaces(usingkeywords)Automaticfreesurfacegenerationonbumperelements:*SURFACE,NAME=BUMPER-EXTBUMPER,Discreterigidsurfaces:*RIGIDBODY,ELSET=BOTDIE,REFNODE=BOTRP*SURFACE,NAME=BOTPLATEBOTDIE,SPOS*RIGIDBODY,ELSET=TOPDIE,REFNODE=TOPRP*SURFACE,NAME=TOPPLATETOPDIE,SPOS*RIGIDBODY,ELSET=SHAFTDIE,REFNODE=SHAFTRP*SURFACE,NAME=SHAFTSHAFTDIE,SPOS,1,DefiningContactPairs(4/12),Example(contd):Definesurfaces(usingAbaqus/CAE),ModelTree,Creatediscreterigidpart,Double-clickSurfacestocreateanewsurface.,1,DefiningContactPairs(5/12),Example(contd):DefinecontactpropertiesContactpropertydefinitionsarethesameforgeneralcontactandcontactpairs.Contactpropertiesmayinclude:friction,contactdamping,andpressure-overclosurerelationships.Inthejouncebumperexample,allcontactpairsusethesameinteractionproperty:*SURFACEINTERACTION,NAME=Friction*FRICTION0.05,2,DefiningContactPairs(6/12),Example(contd):DefinecontactpairsAcontactpairdefinitionisrequiredforeachpairofsurfacesthatcaninteract.Bumperself-contact:*CONTACTPAIR,INTERACTION=FRICTIONBUMPER-EXT,3,DefiningContactPairs(7/12),Example(contd):DefinecontactpairsContactbetweenthebumperandtherigidbodies:*CONTACTPAIR,INTERACTION=FRICTIONBUMPER-EXT,TOPPLATEBUMPER-EXT,BOTPLATEBUMPER-EXT,SHAFT,3,DefiningContactPairs(8/12),Example(contd):SummaryStepstodefinecontactpairs:Definesurfacesbasedontheunderlyingelementsorgeometry.Definesurfaceinteractionproperties:friction,softenedlayers,etc.Definepairsofsurfacesthatcaninteract.Results:,1,2,3,DefiningContactPairs(9/12),3Dcontactpairs:AutomaticcontactdetectionAutomaticcontactdetectionisafastandeasywaytodefinecontactpairsandtieconstraintsinathree-dimensionalmodel.Insteadofindividuallyselectingsurfacesanddefiningtheinteractionsbetweenthem,youcaninstructAbaqus/CAEtoautomaticallylocateallsurfacesinamodelthatarelikelytointeractbasedoninitialproximity.Canbeusedtodefinecontactwithshells,membranesandsolidsIncludingshelloffsetNativeororphanmeshparts,DefiningContactPairs(10/12),Example:DiskbrakeAtabulardisplayofpossiblecontactpairsisprovided,DefiningContactPairs(11/12),TableoperationsandruleseditorEditmultiplecellsCustomizethetabulardisplayOthertableoperationsModifyrulesappliedtonewcontactpairs,DefiningContactPairs(12/12),Non-overlappingsurfacesCanincludeorfilterout,DistanceiswithinsearchtoleranceButsurfacenormalsdonotintersecttheopposingsurface(nonoverlapping),Nocontactpairsdetected,Twocontactpairsdetected,DefiningSurfacesforContactPairs(1/10),Twoapproachesareavailableforsurfacedefinition:Specifythefacesofeachpartinstance(orelement/elementsetfororphanmeshes)thatmaycomeincontact(asshownearlier).AllowAbaqustodeterminethe“freesurfaces”thatmaycomeintocontactautomatically.Onlyavailablethroughthekeywordsinterface(i.e.,wheneditinganinputfile).,DefiningSurfacesforContactPairs(2/10),User-specifiedcontactfaces:Abaqus/CAEinterfaceSolidbodiesThesurfaceonasolidisdefinedbyselectingtheappropriateregionoftheexteriorofthepart.Regionsmaybeselectedindividuallyorbasedonfaceangles.,DefiningSurfacesforContactPairs(3/10),User-specifiedcontactfaces:Abaqus/CAEinterface(contd),ShellsandbeamsThesurfaceonashell/membraneorbeam/trussisdefinedbychoosingtheappropriatesideofthepart.Double-sidedshell/membranesurfacesareallowedforsurface-to-surfaceformulation.SeeLecture3.,DefiningSurfacesforContactPairs(4/10),User-specifiedcontactfaces:KeywordsinterfaceUsefaceidentifierstospecifyeachelementfaceformingthesurface.Example:4-nodequadelement(CPE4,CAX4,etc.).*SURFACE,NAME=EXAMPLE1,S41,S12,S12,S2.Eitherelementsetnamesorelementnumberscanbeusedtospecifysurfaces.,DefiningSurfacesforContactPairs(5/10),User-specifiedcontactfaces:Keywordsinterface(contd)Structuralelementnormalsdictatethedirectionofexpectedcontact:Nodenumberingdictatesthepositivenormaldirection(basedontheright-handrule).Positivenormaldirection=SPOSsurface.Negativenormaldirection=SNEGsurface.Omitsurfaceidentifiertodefineadouble-sidedsurface(shellsandmembranesonly),Shellsandmembranes(S4R,S8R,M3D4,etc.),2-Dtrussesandbeams(B21,T2D2,etc.),DefiningSurfacesforContactPairs(6/10),Automaticorfreesurfacegeneration(Keywordsinterfaceonly)Surfacescanbegeneratedautomaticallyformeshescontainingsolid,continuumshell,andcohesiveelements.Automaticsurfacegenerationisonlyavailablethroughthekeywordsinterface(i.e.,wheneditinganinputfile).Syntax:Omitfaceidentifiersfromthesurfacedefinition.*SURFACE,NAME=EXAMPLEELSET1,ELSET2,100,DefiningSurfacesforContactPairs(7/10),GeneralrulesforsurfacedefinitionsAllelementsunderlyingasurfacemustbecompatible.Theymustbe:Ofthesamedimension(two-orthree-dimensional).Fortwo-dimensionalsurfaces:allplanarorallaxisymmetric(butnotboth).Ofthesameorderofinterpolation(first-orsecond-order).Alldeformableorallrigid(butnotboth).,DefiningSurfacesforContactPairs(8/10),AdditionalrestrictionsSurfacenormalsSurfacenormalsmustbeconsistentBeam,shell,andmembranesurfacescanbeflippedtocreateavalidsurfacedefinitionforcontactMastersurfacenormalsshouldpointtowardtheslavesurface.Otherwise,convergencedifficultieswilloccur.RigidsurfacesAllsurfacesdefinedonrigidbodiesmustbespecifiedasmastersurfaces.,DefiningSurfacesforContactPairs(9/10),Additionalrestrictionsapplytocontactsurfacesdependingonthetypeofcontactformulation.Thesearesummarizedinthefollowingtable:,T-intersection,Surfaceconnectedatonenode,DefiningSurfacesforContactPairs(10/10),Node-basedsurfacesAlternativewaytodefinepointsforcontact.Node-basedsurfaces:Containonlynodes.Arealwaysconsideredslavesurfaces.Precludetheuseofthesurface-to-surfacediscretization.,DefiningGeneralContact(1/13),Theuserinterfaceallowsforaconcisecontactdefinitionreflectingthephysicaldescriptionoftheproblem.Thecontactdefinitioncanbeexpandedincomplexity,asappropriate.Independentspecificationofthecontactinteractiondomain,contactproperties,andsurfaceattributesispermitted.Minimalalgorithmiccontrolsarerequired.,DefiningGeneralContact(2/13),Master-slaverolesareassignedautomaticallyPrimarilybasedonmeshrefinement,Internal,componentsurfacesrankedbysuitabilityasmaster,Overallgeneralcontactsurface,DefiningGeneralContact(3/13),Example:AnalysisofajouncebumperAjouncebumperisahighlycompressiblecomponentthatisusedaspartoftheshockisolationsysteminavehicle.Theanalysisconsistsoftwosteps:Step-1Interferencefitbetweenthebumperandtheshaft.Step-2Movethebottomplateuptocompressthebumper.Wenowconsiderthisproblemusinggeneralcontact.Discreterigidbodiesareusedsinceanalyticalrigidsurfacesarenotcurrentlysupportedbygeneralcontact,DefiningGeneralContact(4/13),Example:AnalysisofajouncebumperThecontactinteractionisdefinedasfollows:1)Beginthegeneralcontactdefinition.*Contact*ContactInclusions,ALLEXTERIOR2)Acceptthedefaultcontactdomain.3)Assignglobalcontactproperties*ContactPropertyAssignment,FRICTION,DefiningGeneralContact(5/13),Thecontactdefinitioncangraduallybecomemoredetailed,ascalledforbytheanalysisGlobal/localfrictioncoefficientsandothercontactpropertiescanbedefined.Pair-wisespecificationofcontactdomain(insteadofALLEXTERIOR)isallowed.ContactinclusionsandexclusionsUsercontrolofcontactthickness(especiallyforshells)isprovided.SurfacepropertiesContactinitialization(initialadjustments,interferencefits,etc.),DefiningGeneralContact(6/13),Toenhanceageneralcontactdefinition,youoftenneedtodefinespecificcontactsurfaces.Surfacescanspanunattachedbodies.Surfacescanincludebothdeformableandrigidregions.Surfacescanhavemixedparentelementtypes.Adjacentshellandsolidfaces,etc.Morethantwofacescanshareacommonedge.AllowsdirectmodelingofT-intersections,etc.,DefiningGeneralContact(7/13),InAbaqus/CAEsurfacescanbecreatedatthepartlevelortheassemblylevel.Surfacesdefinedonapartareavailableintheassemblyforeachinstanceofthepart.BooleanoperationscanbeperformedonsurfacestogenerateothersurfacesusingtheModelTree.Intheinputfile,surfacesaredefinedwiththe*SURFACEkeywordoption.Booleanoperationscanbeperformedonsurfacestogenerateothersurfacesusingtheparameter:COMBINE=UNION|INTERSECTION|DIFFERENCE.*Surface,name=surf_contact,combine=DIFFERENCEelset_main,elset_no_contact,SelectsurfacesintheModelTreeandclickmousebutton3.,DefiningGeneralContact(8/13),Example:NondefaultcontactdomainForsomemodelsthedefaultALLEXTERIORsurfaceisnotappropriateornotsufficient.Thegeneralcontactdomaincanbemodifiedbyincludingand/orexcludingpredefinedsurfaces.Inthejouncebumpermodel,asafeguardagainstcontactbetweentherigidbodiescanbeintroducedusingcontactexclusions,Notethatinthisexamplethisstepisnotrequiredsincethenormalsbetweentheshaftandtheplatesremainperpendicular(contactwillnotbedetected).,DefiningGeneralContact(9/13),Example:NondefaultcontactdomainKeywordsinterface:,*Contact*ContactInclusions,ALLEXTERIOR*ContactExclusionsTOPPLATE,SHAFTTOPPLATE,BOTPLATESHAFT,BOTPLATE*ContactPropertyAssignment,FRICTION,DefiningGeneralContact(10/13),Example:ContactinitializationThedefaultbehaviorofgeneralcontactistoadjustsmallinitialoverclosureswithoutstrain.Cantreatinsteadasinterferencefits.,DefiningGeneralContact(11/13),Example:ContactinitializationKeywordsinterface:,*ContactInitializationData,name=Fit-1,INTERFERENCEFIT*Contact*ContactInclusions,ALLEXTERIOR*ContactPropertyAssignment,FRICTION*ContactinitializationAssignmentBUMPER-EXT,SHAFT,Fit-1,DefiningGeneralContact(12/13),Nondefaultcontactpropertiesmaybeusedtoenhancecontactmodeling.Contactpropertiesmayinclude:Contactpressure-overclosurerelationshipFrictionContactdampingThedefaultsare:A“hard”pressure-overclosurerelationshipnocontactpressureuntilnodesareincontactunlimitedcontactpressureoncecontacthasbeenestablishedNofrictionNocontactdamping,DefiningGeneralContact(13/13),Example:MultiplecontactpropertiesBoltedflangeassemblyCoefficientoffrictionm=0.1forallcontactinteractionsexceptforthoseinvolvingthegasket(m=0.4).,*ContactPropertyAssignment,Friction-0p1,gasketAll,Friction-0p4,ObjectivesWhenyoucompletethisexerciseyouwillbeabletoextractallthefilesnecessarytocompletethedemonstrationsandworkshopsassociatedwiththiscourseWorkshopfilesetup(option1:installationviaplug-in)Fromthemainmenubar,selectPlug-insToolsInstallCourses.IntheInstallCoursesdialogbox:Specifythedirectorytowhichthefileswillbewritten.Choosesthecourse(s)forwhichthefileswillbeextracted.ClickOK.,WorkshopPreliminaries(1/2),5minutes,Workshopfilesetup(option2:manualinstallation)FindoutwheretheAbaqusreleaseisinstalledbytypingabqxxxwhereamiwhereabqxxxisthenameoftheAbaqusexecutio