Calculation of stress intensity factors for curved cracks in anisotropic FGMs

A combined analytical and numerical method is proposed for computation of mixed-mode stress intensity factors (SIFs) for arbitrary curved cracks in anisotropic functionally graded materials (FGMs). By developing a pair of closed-form expressions that relate the SIFs and the J_k-integrals, it is anticipated that the SIFs can be properly extracted should the J _k-integrals be accurately evaluated. To this end, a novel method for calculating the J_k-integrals is presented and has proved reasonably accurate in numerical computations. Since neither a priori information nor extra auxiliary solutions corresponding to the singular behavior is required, this proposed scheme appears to be applicable to problems containing arbitrary shapes of curvature in generally anisotropic FGMs.