Size effect investigation of a central interface crack between two bonded dissimilar materials

This paper focuses on the fracture process connected with a finite central crack along the plane interface between two bonded dissimilar materials under biaxial loading. The analytical solution, based upon the complex potential technique, stems from the boundary value problem formulated for the interfacial crack model subjected to biaxial loading at infinity. Numerical solutions of the interfacial crack problem, based on a Finite Element Method (FEM) formulation, are worked out with reference to external loadings applied at the boundary of a bonded finite plate with the same interfacial crack. Models of different material properties, interface crack lengths, biaxial loading conditions and interfacial fracture strengths are investigated. The analytical and numerical results of this study are examined to see how they are similar and how they are different, when the ratio of the dimension of the bonded finite plate L to the interfacial crack length 2a is varied. A local fracture criterion, for the damaged composite elastic system, involves a suitable defined radial distance from the crack tip, as well as singular and non-singular stress terms. The crack extension at the interface, or its deviation into one of the two dissimilar media, are graphically shown and discussed.