BOUNDARY ELEMENT ANALYSIS OF COMPLEX STRESS INTENSITY FACTORS OF BIMATERIAL INTERFACE CRACKS

The asymptotic crack-tip field for bimaterial interface cracks exhibits an oscillatory behavior which is quite different from that for cracks in homogeneous materials. Modeling such interface cracks by the conventional solution procedures designed for homogeneous materials is inadequate, and may not lead to accurate solutions. This paper introduces a new set of novel special crack-tip elements for analysis of interface cracks in linear elastic bimaterials by using the boundary element method (BEM). The method can properly describe the oscillatory displacement and stress fields in the vicinity of the interfacial crack-tip. Furthermore, the troublesome nearly-singular integrals, which are crucial in the application of the BEM for ultra-thin structural problems, are calculated accurately by using a nonlinear coordinate transformation. Accurate and reliable BEM results with only a small number of boundary elements can be obtained for interface crack analysis of ultra-thin composite bimaterials.