A closed-form analytical variational approach to thermally induced thin-film delamination

Abstract

Thin polymeric films applied on stiff substrates are prone to delamination upon thermal loading. Different thermal expansion coefficients and different elastic properties can cause localized stress concentrations in the interface between applied layer and substrate. The present work proposes a variational approach to compute residual stresses and strains within the film. Using finite element calculations, it is shown that the presented closed-form analytical solution provides accurate interfacial stresses. Employing a critical distances failure criterion, these stresses are used to predict thermally induced crack nucleation. The proposed model is validated using experimental data of thermally loaded epoxy–glass specimens. It is in good agreement with the test data and provides predictions for thin-film delamination.