Multiple film cracking in film/substrate systems with residual stresses and unidirectional loading

Multiple film cracking in film/substrate systems is analyzed in the present study. Specifically, the experimental measurements of multiple cracking of SiO x films of various thicknesses on polyethylene terephthalate substrates are analyzed. The system is subjected to both residual stresses and unidirectional tensile loading. Considering a three-dimensional geometry, an analytical model is developed to derive the stress distribution in the system, and the film-cracking problem is analyzed using both the strength and the energy criteria. Compared to the strength criterion, the energy criterion shows better agreement with the measurements of the crack density versus applied strain relation.