THE EFFECT OF INTERFACIAL FRICTION ON THE BUCKLE-DRIVEN SPONTANEOUS DELAMINATION OF A COMPRESSED THIN-FILM

We consider the process of frictional interaction during the delamination of a compressed thin film from a substrate in order to assess the effect of Coulomb friction on the energy release rate, G, driving the delamination. For the case in which the film and the substrate have identical elastic properties, we derive a singular integral equation for the relative sliding displacement of the opposing faces of the debonded interface. Using an analytical model, we find that G decreases by about 35% when the coefficient of interfacial friction is equal to one. Using finite element methods, we then investigate the effects of compliance differences between the film and the substrate, as well as the bending that arises during the post-buckling response of the film. We find that, when the film is more compliant than the substrate, frictional interaction is enhanced and the calculated energy release rate decreases substantially. We further find that, when bending forces are taken into account, G is significantly affected only when the ratio of the length of the delamination to the thickness of the film is relatively small. We conclude that frictional effects can be significant in reducing the delamination driving force, and they can play an important role in the observed arrest of spreading delaminations.