Abstract :
SingleparameterssuchasthestressintensityfactorKorJ-integralintraditionalfracturemechanicsdependstronglyonthegeometryandloadingconditions.ThereforeasecondparameterliketheT-stressmeasuringthestressconstraintisadditionallyneededtocharacterizegeneralcrack-tipfields.WhilemanyresearchworkshavebeendonetoverifytheJ–Tdescriptionofelastic–plasticcrack-tipstressfieldsinplanestrainspecimens,alimitedamountofwork(especiallyforbimaterials)hasbeenperformedtodescribethestructuralsurfacecrack-frontstressfieldswithtwoparameters.Onthisbasis,viadetailed3Dfiniteelement(FE)analysesforsurface-crackedplatesandpipesofhomogeneousmaterialsandbimaterials,weinvestigatetheextendedvalidityorlimitationofthetwoparameterapproach.Weherefirstdevelopafull3Dmesh-generatingprogramforsemi-ellipticalsurfacecracks,andcalculateelasticT-stressfromtheobtainedFEstressfieldfor“purelyelastic”jointwithmodulusmismatch.WethenvalidatetheJ–Tmethodologyincharacterizingthesurfacecrack-frontfieldsofweldedplatesandpipesundervariousloadingsbycomparingtheJ–Tpredictionstothe“elastic–plastic”3DFEstressfields.
