Impacts of residual stresses on J-integral for clamped SE(T) specimens with weld centerline cracks

Three-dimensional (3D) finite element analyses (FEA) are performed on clamped single-edge notched tension (SE(T)) specimens to investigate the impact of residual stresses on the average J-integral (J) evaluated over the crack front. Both shallow- and deeply-cracked (i.e. a/W = 0.2 and 0.5) specimens are considered in the analysis. The residual stresses are introduced by different mechanical pre-loading techniques and consistent with those measured from pipeline girth welds and those specified in well-known structural integrity assessment standards. The analysis results indicate that the impact of the residual stress on J depends strongly on the pre-loading techniques employed for the generation of residual stresses and level of the primary loading applied to the SE(T) specimen.