Stress intensity factor computation along a non-planar curved crack in three dimensions

In this paper, a numerical procedure, incorporated with the finite element method, is developed for calculation of the mixed-mode stress intensity factors along a 3D curved crack with non-planar surfaces. The approach is formulated by modifying the concept of the J_k- and G_III-integrals. Note that the property of path-independence for curved cracks does not hold in a manner as that for straight cracks and needs to be properly modified. As a consequence, the near-front region is always included in the integration. An appropriate numerical method is therefore developed for simulating the associated singular behavior. Since no extra auxiliary solutions are required for the computation, the proposed method appears to be versatile and can be used for evaluation of the stress intensity factors associated with crack front and crack surfaces of arbitrary curvatures.