Effects of the surface crack shape on <i>J</i> values along the front of an elliptical crack

Abstract Surface cracks are one of common forms of flaws in thin‐walled structures such as pressure vessels, oil, and gas pipelines. Accurate evaluation of the growth driving force of such surface cracks is important for integrity analyses of these structures. In this study, the combined effect of the depth and the length of a given surface crack under tension was analyzed using combined elastoplastic finite element analysis (EPFEA) and crack propagation experiments with selected crack shapes. Based on the consideration of the distribution profile of the J integral as the crack growth driving force along crack front, the crack growth stability with different crack shapes was analyzed. Finite element analysis (FEA) results showed that the growth from partial to through‐wall penetration is affected by the shape of the initial crack. As shown by the distribution profile of the J integral along the crack front, the location(s) of the maximum J , that is, the highest crack driving force, is (are) found to vary with the crack shape and development.