Areviewofcreepanalysisanddesignundermulti-axialstressstatesOriginalResearchArticle

Theexistenceofmulti-axialstatesofstresscannotbeavoidedinelevatedtemperaturecomponents.Itisessentialtounderstandtheassociatedfailuremechanismsandtopredictthelifetimeinpractice.Althoughmetalcreephasbeenstudiedforabout100years,manyproblemsarestillunsolved,inparticularforthoseinvolvingmulti-axialstresses.Inthiswork,astate-of-the-artreviewofcreepanalysisandengineeringdesigniscarriedout,withparticularemphasisontheeffectofmulti-axialstresses.Theexistingtheoriesandcreepdesignapproachesaregroupedintothreecategories,i.e.,theclassicalplastictheory(CPT)basedapproach,thecavitygrowthmechanism(CGM)basedapproachandthecontinuumdamagemechanics(CDM)basedapproach.Followingabovearrangements,theconstitutiveequationsanddesigncriteriaareaddressed.Intheend,challengesontheprecisedescriptionofthemulti-axialcreepbehaviorandthenimprovingthestrengthcriteriainengineeringdesignarepresented.