Interfacial stresses in bi-material system subjected to an exteranl shear force

Interfacial stresses developed at the free edge of bi-material system are the main driving factors for the initiation of delamination. To minimize such failure in multilayered eletronic assemblies and packages, it is important to develop a better understanding of the stress distribution at the interface. In this paper, the peeling stress and shear stress at the interface of a bi-material system subjected to an external shear force are evaluated based on elastic foundation theory. In order to investigate the effect of geometry and material properties on peeling and shearing stress at the interface, both young's modulus ratio and thickness ratio of material 1 and material 2 were examined in the study. The results were compared against those from finite element analysis and good correlation was observed. The discussion provides a better insight into results from typical button shear tests frequently used in the industry.