Interfacial Crack Propagation in a Thin Viscoelastic Film Bonded to an Elastic Substrate
Edge decohesion along the interface of a thin viscoelastic film bonded to an elastic substrate under tensile residual stresses is considered. The tensile residual stress in the film is replaced by a combination of edge loads, and an explicit relation of strain energy with respect to time is obtained through simple beam analysis. The strain energy function is discretized into time steps which are assumed to be very small so that the dissipation effects over the time steps can be neglected. The energy release rate is then calculated using a Griffith type energy balance. An analytical model is developed to predict the crack growth and its velocity. Extent of crack growth along the interface is prediced based on a fracture criteria. The analytical predictions are compared with results from a viscoelastic finite element analysis.
© 1994 Kluwer Academic Publishers. Received 9 August 1993; accepted in revised form 30 November 1993. This work was supported by the IBM-Caltech cooperative research fund. We thank Professor W.G. Knauss for several helpful discussions and suggestions. We would also like to thank Dr. Sundar Karnath of IBM for his interest and support. The helpful comments provided by the Editor-in-Chief, Professor M.L. Williams are greatly appreciated.