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ANSYS/LS-DynaMulti-MaterialALEModelingPresentedBy:StevenHale,M.S.M.E.ComputerAidedEngineeringAssociates,Inc.ComputerAidedEngineeringAssociates,Inc.APDL-2Multi-MaterialALEBasicszWhatistheMulti-MaterialALEmethod(MMALE)—MMALEstandsforMulti-MaterialArbitraryLagrangianEulerian—CombinesLagrangianandEulerianmethods•Lagrangianstep–meshmoveswiththematerialinthefirstpartofthestep•Eulerianstep–themeshissmoothedouttominimizeelementdistortionandmaterialflowsbetweenelements.Thisisalsoknownastheadvectionstep.•ADVANTAGEoverapureEulerianmethod–Elementsareallowedtomoveanddistortwhichminimizesadvection.Thisminimizesenergydissipationandspeedsupruntime.ComputerAidedEngineeringAssociates,Inc.APDL-3Multi-MaterialALEBasicszMMALErequiresadomainmeshwithsomeelementsthatcontainsolidorfluidmaterials.•Theouterelementsofthedomainmeshtypicallycontainavacuumorfluidmaterial.•Solidmaterialsarethenassignedtoelementswithinthedomainmesh.—*INITIAL_VOLUME_FRACTIONcanbeusedtoassignvolumefractionsofdifferentmaterialsineachelementofthedomainComputerAidedEngineeringAssociates,Inc.APDL-4SupportforMMALEinANSYSzTheANSYSpre-processordoesnotsupportinputsfortheMMALEmethodzThefollowingmodelfeaturescanbeassignedinANSYS:—Geometry—Mesh—Materialproperties—Hourglasscontrols—Boundaryconstraints—Initialvelocities—Timeandoutputcontrols—AllinputsspecifictolagrangianpartszThefollowingmodelfeaturesmustbeaddeddirectlytotheLS-Dynainputfile:—Contactdefinitions—MMALEcontrolsettings:advectioncontrol,meshsmoothing,movement,andexpansioncontrol—MMALEgroupdefinitions–usedtodefinediscreteMMALEpartsComputerAidedEngineeringAssociates,Inc.APDL-5MMALEInputzElementformulation—*SECTION_SOLID—SECID,ELFORM•ELFORM=5(single-materialALE)•ELFORM=6(pureEulerian)•ELFORM=11(multi-materialALE)*ComputerAidedEngineeringAssociates,Inc.APDL-6MMALEInputz*CONTROL_ALE:MMALEcontrolsettings—DCT,NADV,METH,AFAC,BFAC,CFAC,DFAC,EFAC•DCT(ignored)•NADV:Numberoftimestepsbetweenmeshsmoothingandadvectioncycles—Canspeedupruntimebutreducestability•METH:Advectionmethod—Meth=1(1storderadvecton–fast,validforfluidsonly)—Meth=2(2ndorderadvection–slower,minimizesenergyloss)•AFAC,BFAC,CFAC,DFAC:Meshsmoothingparameters—AFAC=-1(nosmoothing),1(simpleaveragesmoothing)•-1doesnotallowelementdistortion,onlyexpansionandcontraction•1simpleaveragemethod–commonlyused—BFAC=1(volume-weightedsmoothing)—CFAC=1(isoparametricsmoothing)—DFAC=1(equipotentialsmoothing)-commonlyused—EFAC=1(equilibriumsmoothing)ComputerAidedEngineeringAssociates,Inc.APDL-7MMALEInputzComputerAidedEngineeringAssociates,Inc.APDL-8MMALEInputz*ALE_MULTI-MATERIAL_GROUP—DefinesMMALEgroups—Part/SetIDlistComputerAidedEngineeringAssociates,Inc.APDL-9MMALEInputz*ALE_REFERENCE_SYSTEM_GROUP—DefinesthemotionoftheALEmeshComputerAidedEngineeringAssociates,Inc.APDL-10MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-11MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-12MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-13MMALEInputz*CONSTRAINED_LAGRANGE_IN_SOLID—DefinescontactbetweenMMALEgroupsandLagrangianelementsSlavepartmustbelagrangian,MasterpartisMMALECTYPE=2(constrainedacelandvel(default).Cannotbeusedwithrigidbodies.Doesnotconserveenergy)CTYPE=4(penaltycouplingwithouterosion)CTYPE=5(penaltycouplingwiherosioninLagrangianpart)DIREC=1(gluedtogetherintensionandcompression)DIREC=2(compressiononly)ComputerAidedEngineeringAssociates,Inc.APDL-14MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-15MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-16MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-17MMALEInputComputerAidedEngineeringAssociates,Inc.APDL-18Example:LagrangeSphere–MMALEBlockzMMALEInput—DefinescontactbetweenMMALEgroupsandLagrangianelements$$2ndorderadvection,Nosmoothing*CONTROL_ALE,1,2,-1.,*ALE_MULTI-MATERIAL_GROUP2,13,1$$ALEmeshmotion/expansioncontrol$7=norotations*ALE_REFERENCE_SYSTEM_GROUP4,0,4,0,5,3,7,0,0,0,,$$DefinecouplingbetweenPart1(ALE)andPart3(Lagrangian)$Use2x2quadrature*CONSTRAINED_LAGRANGE_IN_SOLID1,4,1,0,-2,4,2,1,,$*SET_PART_LIST4,2,3,