Interface inclusion problems in laminated medium

A moduli perturbation method is used to construct the solution for the contact stiffness in the inclusion problem of a composite laminate under a state of torsional deformation. The inclusion is considered to be embedded at the interface of the laminate. The following solutions have been obtained: (i) the exact solution for the inclusion in a medium consisting of two layers and two half- spaces, (ii) a first-order accurate solution for a layered medium consisting of $(n+m)$ constituents, (iii) an approximative solution for a physically inhomogeneous medium as the limiting case of the layered medium.