损伤初始及扩展资料.doc

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1、__________________________________________________DamageinitiationcriterionanddamageevolutionresponseAbaqus/StandardandAbaqus/Explicitofferageneralcapabilityforpredictingtheonsetoffailureandacapabilityformodelingprogressivedamageandfailureofductilemetals.In

2、themostgeneralcasethisrequiresthespecificationofthefollowing:·theundamagedelastic-plasticresponseofthematerial();·adamageinitiationcriterion();and·adamageevolutionresponse,includingachoiceofelementremoval().Damageinitiationcriterion·Damageinitiationcriteria

3、forthefractureofmetals,includingductileandshearcriteria.·Damageinitiationcriteriafortheneckinginstabilityofsheetmetal.Theseincludeforminglimitdiagrams(FLD,FLSD,andMSFLD)intendedtoassesstheformabilityofsheetmetalandtheMarciniak-Kuczynski_____________________

4、_______________________________________________________________________________(M-K)criterion(availableonlyinAbaqus/Explicit)tonumericallypredictneckinginstabilityinsheetmetaltakingintoaccountthedeformationhistory.Morethanonedamageinitiationcriterioncanbesp

5、ecifiedforagivenmaterial.Ifmultipledamageinitiationcriteriaarespecifiedforthesamematerial,theyaretreatedindependently.Damageevolution Thedamageevolutionlawdescribestherateofdegradationofthematerialstiffnessoncethecorrespondinginitiationcriterionhasbeenreach

6、ed.FordamageinductilemetalsAbaqusassumesthatthedegradationofthestiffnessassociatedwitheachactivefailuremechanismcanbemodeledusingascalardamagevariable,  (),where  representsthesetofactivemechanisms.Atanygiventimeduringtheanalysisthestresstensorinthematerial

7、isgivenbythescalardamageequationwhere D istheoveralldamagevariableand  istheeffective(orundamaged)stresstensorcomputedinthecurrentincrement.  arethestressesthatwouldexistinthematerialintheabsenceofdamage.Thematerialhaslostitsload-carryingcapacitywhen .Bydef

8、ault,anelementisremovedfromthemeshifallofthesectionpointsatanyoneintegrationlocationhavelosttheirload-carryingcapacity.Input File Usage:          Usethefollowingoptionimmediatelyafterthecorresponding o