High temperature fracture parameter for a weld interface crack

A fracture parameter is introduced to characterize crack growth at elevated temperature for a weld interface crack. Finite element analyses are made for a compact tension (CT) specimen under constant load where an interface is modeled along the crack plane to simulate the dividing line of the weld metal (WM) and base metal (BM). A constitutive relation for an elastic-creeping material is used. The proposed time dependent fracture parameter is obtained for different creep constants of WM and BM. A transition time and fracture parameter for the homogeneous and welded specimens are defined such that the results can be normalized and presented in a general form for assessing the crack growth life.