Energy Changes In a Stressed Unbounded Matrix Containing a Inhomogeneity Due to Formation of a Non-perfect Interface

In the present paper, the roles of a linear spring interface and a membrane shell interface on the mechanical behaviour of a bimaterial are investigated by using a simplified matrix-inhomogeneity elastic system. The system consists of a circular inhomogeneity embedded in an unbounded matrix and is in shear deformation, either coming from a remote uniform stress applied in the matrix, or from a uniform shear transformation in the inhomogeneity. It was shown that, if a perfect interface of the system is transformed to a spring-type one, while the system is stressed by the above loadings, the change in the total potential energy is negative. The opposite occurs, if a membrane shell interface is formed in the stressed system. The elastic energies stored in the system constituents are determined by considering the interface as a separate phase of the system.