SOME PHENOMENA OF CRACKS PERPENDICULAR TO AN INTERFACE BETWEEN DISSIMILAR ORTHOTROPIC MATERIALS

The problem of two aligned orthotropic materials bonded perfectly alon g the interface with cracks embedded in either one or both of the mate rials while their directions being perpendicular to the interface is c onsidered. A system of singular integral equations for general anisotr opic materials is derived. Employing four effective material parameter s proposed by Krenk and introducing four generalized Dundurs' constant s, the kernel functions appearing in the integrals are converted into real forms for the present problem which are keys to the present study . The kernel functions for isotropic dissimilar materials can be deduc ed from the present results directly, no any limiting process is neede d. These kernel functions are then employed to investigate the singula r behaviors for stresses at the point on the interface. Characteristic equation which determines the power of singularity for stresses is gi ven in real forms for the case of cracks that are going through the in terface. Studies of the characteristic equation reveal that the singul ar nature for the stresses could vanish for some material combinations and the singular nature for the stresses is found to be independent o f the replacement of the material parameter Delta by Delta(-1). The ke rnel functions developed are further used to explore analytically some interesting phenomena for the stress intensity factors, which are dis cussed in detail in the present context. Some numerical results for th e stress intensity factors for a typical dissimilar materials are also given.