Effect of thermal and weld-induced residual stresses on the J-integral and CTOD in elastic-plastic fracture analyses

An investigation of how the residual stress of a welded pipe contributes to the CTOD and the J-integral has been performed. Many experiments show that for ductile materials and high L(sub r) values the contribution from the residual stress to the risk of fracture is negligible. The objective of the present numerical analyses is to investigate how the weld residual stresses interact with other types of stresses and if possible give some recommendations on how to treat weld residual stresses in fracture assessments. The welding process has been simulated according to generally accepted methods in order to obtain a proper plastic strain field. The results imply that although the relative contribution of the residual stress to fracture decreases rapidly for high L(sub r), the residual stress still makes a contribution even for quite high loads.