Delamination from interfaces between dissimilar materials is the primary cause of failure in electronic packages. Fracture mechanics is a powerful tool for the evaluation of delamination. However, many materials used in electronic packages such as composite materials and single crystals are anisotropic materials. Stress intensity factors of an interface crack between dissimilar anisotropic materials which proposed by Hwu are useful for evaluating the reliability of plastic packages. However, numerical methods that can analyze the stress intensity factors of an interface have not been developed. We propose herein a new numerical method for the analysis of an interface crack between dissimilar anisotropic materials. The stress intensity factors of an interface crack are based on the generalized plane strain condition. The energy release rate is obtained by the virtual crack extension method in conjunction with the finite element method for the generalized plane strain condition. The energy release rate is separated into individual modes of stress intensity factors, KI, KII, and KIII, using the principal of superposition. The target problem to be solved is superposed on the asymptotic solution of displacement in the vicinity of an interface crack tip, which is described using the Stroh formalism. Analyses of the stress intensity factors of center interface cracks between semi-infinite dissimilar anisotropic media subjected to concentrated self-balanced loads on the center of crack surfaces as well as to uniform loads are demonstrated. The present method accurately provides the mode-separated stress intensity factors using relatively course meshes for the finite element method.

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