LS-DYNA复合材料建模教程

ModelingofCompositesinLS-DYNASomeCharacteristicsofCompositesOrthotropicMaterialCoordinateSystemUser-definedIntegrationRuleforShellsOutputforCompositesSomeCharacteristicsofSeveralCompositeMaterialModelsinLS-DYNAClosingRecommendationsTwoGeneralClassesofCompositesAdvancedcompositeshavestiff,highstrengthfibersboundinamatrixmaterial.•Eachlayer/lamina/plyisorthotropicbynatureasthefibersruninasingledirection.•Usually,anadvancedcompositesectionwillhavemultiplelayersandeachlaminawithinthestackwillhavethefibersrunninginadifferentdirectionthanintheadjacentlamina.Asandwichcompositesectionhaslaminaewhichmaybeindividuallyisotropicbutthematerialpropertiesandthicknessmayvaryfromlaminatolamina.•Afoamcorecompositeisaparticulartypeofsandwichcompositewhereathick,softlayeroffoamissandwichedbetweentwothin,stiffplies.OrthotropicMaterialsinLS-DYNAOrthotropicmaterialconstantsaredefinedinthematerialcoordinatesystem.Thematerialcoordinatesystemmustbeinitiallyestablishedforeachorthotropicelementand,inthecaseofshells,foreachthrough-thicknessintegrationpointaswell.Thisorientationcomesfromthreesources.•Inthematerialdefinition(*mat)•Seedescriptionof“AOPT”inUser’sManualunder*mat_2(orthotropic_elastic)•Inthesectiondefinition(*section_shell)•A“beta”angleisgivenforeachintegrationpoint•Optionally,intheelementdefinition(*element_shell_beta,*element_solid_ortho)OrthotropicMaterialsinLS-DYNAAsthesolutionprogressesandtheelementsrotateanddeform,thematerialcoordinatesystemisautomaticallyupdated,followingtherotationoftheelementcoordinatesystem.•Theorientationofthematerialcoordinatesystemandthusresponseoforthotropicshellscanbeverysensitivetoin-planeshearingdeformationandhourglassdeformation,dependingonhowtheelementcoordinatesystemisestablished.•Tominimizethissensitivity,“InvarientNodeNumbering”,invokedbysettingINN=2(shells)or3(solids)in*control_accuracyishighlyrecommended.User-Defined(Through-Thickness)IntegrationGaussianorLobattointegrationruleshavepre-establishedintegrationpointlocationsandweights(NIP=10).•LobattoincludesintegrationpointsontheoutsidesurfacesTrapezoidalintegrationhasequallyspacedintegrationpoints.Forcomposites,theusermayneedtodefinehis/herownintegrationpointlocationsandweights(correspondingtoplythicknesses)andmayneedtoreferenceadifferentsetofmaterialconstantsforeachintegrationpoint.User-DefinedIntegration(970)*PARTmaterial11111*PARTmaterial22112$---+----1----+----2----+----3----+----4----+----5----+----6-*SECTION_SHELL12-2018.00000018.00000018.00000018.000000*mat_layered_linear_plasticity11,2.7e-6,73.4,0.32,1e9*mat_layered_linear_plasticity12,6.3e-7,0.286,0.3,1e9*INTEGRATION_SHELL20,8,0-.9722,.02778,1-.9167,.02778,1-.6667,.22222,2-.2222,.22222,2.2222,.22222,2.6667,.22222,2.9167,.02778,1.9722,.02778,1*ELEMENT_SHELL1112333221233433NegativevalueindicatesuserintegrationruleUser-DefinedIntegration(971)$no*sectioncommandneeded$thicknessissumofthickvaluesgivenin*PART_COMPOSITE$noneedformultiple*PARTcommands$*PART_COMPOSITE$pid,elform1,2$mid,thick,beta,,mid,thick,beta11,0.5,,,11,0.512,4.0,,,12,4.012,4.0,,,12,4.011,0.5,,,11,0.5*mat_layered_linear_plasticity11,2.7e-6,73.4,0.32,1e9$NOTE:foamcorecoulduseadifferent$materialmodel(971)*mat_layered_linear_plasticity12,6.3e-7,0.286,0.3,1e9*ELEMENT_SHELL1112333221233433OutputforCompositesForcompositematerialmodels,stresses(andstrains)willbewritteninthematerialcoordinatesystemratherthantheglobalcoordinatesystemifCMPFLG(andSTRFLG)issetto1in*database_extent_binary.•Usefuloptionforpostprocessingoffiberandmatrixstresses.SetMAXINTin*database_extent_binarytothetotalnumberofthrough-thicknessintegrationpointsinyourcompositeshell.Bydefault,stressesonlyatthetop,bottom,andmiddleintegrationpointsarewritten.OutputforCompositesSomecompositematerialmodelshave“extrahistoryvariables”thathelptotrackmodesoffailureineachintegrationpoint.(SeematerialdocumentationintheUser’sManualfordetails.)•NEIPS(shells)orNEIPH(solids)in*database_extent_binaryshouldbesettothenumberofextrahistoryvariablesneeded.•Forexample,ifyouwanttotrackthedamageparameter(6thextrahistoryvariable)inmat_054,setNEIPSto6.CompositeMaterialModels*mat_2(elastic_orthotropic)•9elasticconstants(solids);6elasticconstants(shells).•TotalLagrangianformulation(okayforlargeelasticdeformations).•Nofailurecriteria.Eachofthefollowingorthotropicmaterialsofferaparticularbrandoffiber/matrixdamageandfailurecriteria.Upto5strengthvaluesaregiven(XT,XC,YT,YC,SC).•*mat_22(composite_damage)•*mat_54,55(enhanced_composite_damage)•*mat_58(laminated_composite_fabric)•*mat_158like58butincludesstrainrateeffects•*mat_59(composite_failure(_shell,_solid)_model)•Mats22and59canbeusedwithshellsandsolidsCompositeMaterialModelsThepaperCrashworthinessAnalysiswithEnhancedCompositeMaterialModelsinLS-DYNA-MeritsandLimits,Schweizerhofetal,5thInternationalLS-DYNAUser'sConference(1998)providessomeinsightintoseveralcompositematerialmodelsinLS-DYNA,includingmat_54,mat_58,andmat_59.Thispaper(inPDFformat)andotherfiles/examplesrelatedtocompositesareavailablein