HRR Dominance and J-integral as Fracture Parameter in Heterogeneous Welded Joint

HRR-dominace and the application feasibility of J-integral in heterogeneous welded joints is investigated by Moire interferometry of reflected sticking film.The results showed that at least for cases studied in this paper,for either the welded joint of steel A537 welded by electrode LB52NS with an overmatching weld in strength or the welded joint of steel 9% Ni welded by electrode OK69.45 with an undermatching weld in strength,HRR-dominance is failure in horizontal displacement field while the slope of lgv-lgr in vertical displacement field is not agreement with 1/(n+1) of base metal or weld metal.So,it is doubtful to directly use the J-integral as a fracture criterion in heterogeneous welded joints.By the way,it is also not correct to use sigularity elements in vinicity of the crack tip in welded joint.