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第1页共9页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第1页共9页Chapter3Materialmodelandmaterialcharacterizationofautomotivealuminiumalloy5052H343.1prefaceThebasicpropertyofmaterialdecidestheusefunctionofthestructure.intheresearchofcarcrashesandlargedeformationofkeycomponents,thekeypointofsolvingtheproblemistobuildcorrespondingphysics-mathmodelinordertoacquirethespecificmaterialparameters.Asfortheautomotivealuminiumalloyinourresearch,weneedtoconsidertheresponsecharacteristicofthematerialmachanismonconditionofrealimpact(suchasdynamicloading,high-stresscondition,includingprimarydefectsordamage,etc).Bythisway,numerousperformancetestandfull-sizecomponnetcrashtestneedtobeconducted,whichwouldexhaustgreatlaborpowerandphysicalresources,buttheresultisstilldubious.Withthelimiteddiscretdataobtainbytheexperiment,itcanhardlycoverthespaceofallsolutionofthemodel.Forsomeextremeconditionsuchasshearingstresscondtion,highstrainrate(ε－1≥2×102),ithardtopredictitsmachanismresponse.Therefore,thismodelwebuilthasitscomparativelylargelimitations.Butcombinewithnumericalsimulations,itcanexpandthespaceofthemodeleffectively,whileobtaincompletematerialparameters.Theresultshowsthattheprecisionofnumericalsimulationislargelydependontheprecisionofmaterialparametertoinput.Intheanalysisoflargedeformation,mater-ialmachanismmustdescribethematerialchangefromelasticdeformation,elastoplasticdeformation,damageprogession,evolvement,fracture,whichismulti-stepmachanismprocedure.Besides,variousstrainrate,anisotropiccausedbyprocessinghistory,etcneedtobetakeintoaccounttoconsideritsaffectionwithconstitutiverelations.Previously,thisisaextremelycomplexproject,wheremanyproblemsisstillunsolved.J.G.BlauelandD.Z.Su,etcsimplyusedtensilebarexperimentcombinedwithfiniteelementtosimulatethecharacterizationofAW6016automotivealuminiumalloyandcrashtestofthetypicalcomponentsinautomobiles.Itpredictsthestaticanddynamicresponseofthealuminiumalloyandkeycomponentsinmacroperspective,andexpandG-T-Nmodelinmicroperspective,whichexplaintheductilefractureofthealuminiumanditsinitiationandevlovementbymachanismofgrowthofvoids,thatcouldbeappliedinengneeringcalculations.FranckLauroandBrunoBennanibuiltdynamicalloadingmachanismmodelonfinite-elementcalculationterrace.Thismodeltakeelasticflowandanisotropicofmicroholes’damageevolvementintoaccount.Therebythiscouldbeusedtopredictsituationofdamageandfractureofmaterialswithobvioustexture第2页共9页第1页共9页编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第2页共9页deformationsuchasextrudedaluminiumalloysincircumstancesofdynamicloadingwithlargedeformation.TheotheronecontributionofFrank’sresearchistodevelopiterativealgorithmwhichisaexperimentcombinewithnumericalsimulationtoachievesolvingandcorrectthekeyparameterinmaterialmodel.Thismethodusesnotchtensiledataasthebasicinput,whichcanderiveparameterofG-T-Ndamagemodel,andrevisetheseparametersinconsiderofanisotropicfactors.Eventually,theresultofnumericalsimulationhitoffwithexperiments.Incomparewithothermaterialcharacterizationmethod,thiscouldavoidagreatamountofexperimentexpenses,andimprovingtheefficencyofmodelingrate.Ontheotherhand,thismethoddoesnotconsiderthechangesofdamagemachanismofthematerialsunderlowerstresscondition.Theresultprovedthatwhenthreedimensionstressdegreeisbelow1,withthereducingofstressdegree,shearslipfailurewouldtake...