Assessing fracture behaviour of circumferentially TWC elbows subjected to closing and opening moment

Ductile fracture assessments of circumferentially through-wall cracked elbows based on the elastic–plastic J-integral concept are discussed with particular interest in its ability and accuracy to predict experimental results corresponding to initiation of stable crack growth and instability. 3D non-linear finite element analyses were performed considering both material and geometrical non-linearity using the advanced fracture analysis code WARP3D. Using load–displacement variation, the collapse limit load is also calculated by three alternative method and the results are compared with experimental maximum load. Elastic–plastic fracture mechanics based FEM analysis supported with specimen level material evaluation can give an accurate and complete description of component behaviour. The work provides benchmark data to assist in the engineering treatment of cracked piping elbows.