简介：Basedontheexperimentalresultsofsuper-elasticNiTialloy,athree-dimensionalsuper-elasticconstitutivemodelincludingbothofstress-inducedmartensitetransformationandplasticityisconstructedinaframeworkofgeneralinelasticity.Intheproposedmodel,transformationhardening,reversetransformationofstress-inducedmartensite,elasticmismatchbetweentheausteniteandmartensitephases,andtemperature-dependenceoftransformationstressandelasticmodulusofeachphaseareconsidered.Theplasticyieldingofmartensiteoccurredunderhighstressisaddressedbyabilinearisotropichardeningrule.Drucker-Prager-typedtransformationsurfacesareemployedtodescribetheasymmetricbehaviorofNiTialloyintensionandcompression.Thepredictioncapabilityoftheproposedmodelisverifiedbycomparingthesimulatedresultswiththecorrespondentexperimentalones.BasedonbackwardEuler'sintegration,anewexpressionofconsistenttangentmodulusisderived.TheproposedmodelisthenimplementedintoafiniteelementpackageABAQUSbyuser-subroutineUMAT.Finally,thevalidityofsuchimplementationwasverifiedbysomenumericalsamples.

简介：Toconsidertheanisotropicdamageinfatigue,animprovedboom-panelmodelispresentedtosimulatearepresentativevolumeelement(RVE)intheframeworkofcontinuumdamagemechanics.TheanisotropicdamagestateoftheRVEisdescribedbythecontinuityextentsofboomsandpanels,whosedamageevolutionsareassumedtobeisotropic.Thenumericalimplementationisproposedonthebasisofdamagemechanicsandthefiniteelementmethod.Finally,theapproachisappliedtothefatiguelifepredictionof2A12-T4aluminiumalloyspecimenundercyclicloadingoftension-torsion.Theresultsindicateagoodagreementwiththeexperimentaldata.