Numerical simulation of interface crack in thin films

The de-adhesion of a thin film from a rigid substrate is studied. It is ass umed, that a periodic array of micro-cracks exists along the film/substrate interface. During formation, the film expands, while being constrained by the substrate. This phenomenon leads to development of compressive stresses . Then buckling may occur and cause crack growth either along the interface or in the film towards the free surface. A finite element model has been d eveloped, which simulates film buckling and subsequent interfacial crack gr owth, based on film/substrate adhesive constitutive relations. These relati ons have been motivated by atomistic calculations on bimaterial failure. Th e model does not require any facture criterion. Interfacial work of separat ion has a significant effect on damage growth ahead of the crack tip, along the interface. Also, a critical remote compressive stress exists, at which damage progresses without further loading of the film. The relation betwee n the critical compressive stress for extensive damage and the interfacial work of separation can be used in combination with experiments for the quan titative characterization of the film/substrate interface.