Abstract: The fracture problems near the interface crack tip for mode II of double dissimilar orthotropic composite materials are studied. The mechanical models of interface crack for mode II are given. By translating the governing equations into the generalized bi-harmonic equations, the stress functions containing two stress singularity exponents are derived with the help of a complex function method. Based on the boundary conditions, a system of non-homogeneous linear equations is found. Two real stress singularity exponents are determined be solving this system under appropriate conditions about bimaterial engineering parameters. According to the uniqueness theorem of limit, both the formulae of stress intensity factors and theoretical solutions of stress field near the interface crack tip are derived. When the two orthotropic materials are the same, the stress singularity exponents, stress intensity factors and stresses for mode II crack of the orthotropic single material are obtained.

Key words: interface crack for mode II, stress intensity factor, double materials, orthotropic