Stress intensity factors for the inner generative crack induced by the out-of-plane stress in front of the main through-the-thickness crack

摘要

The problem of the inner generative crack induced by the out-of-plane stress in front of the main through-the-thickness crack is discussed. The crack front of the inner generative crack is usually perpendicular to that of the main crack in the high strength pipeline steel. A three-dimensional (3D) semi-analytical method to estimate the stress intensity factor (SIF) of the inner generative crack has been proposed, based on the 3D two-parameter K–T _z approach and Bueckner’s principle of superposition. Detailed comparison of the 3D semi-analytical, finite element (FE) and the corresponding plane strain solutions has been performed. It was shown that the 3D semi-analytical solutions agree well with the 3D FE results and they both are less conservative than the planar solutions. The influence of the inner generative crack on the SIF of the main crack was also analyzed.