Evolution of Wrinkles in Elastic-Viscoelastic Bilayer Thin Films

This paper develops a model for evolving wrinkles in a bilayer thin film consisting of an elastic layer and a viscoelastic layer. The elastic layer is subjected to a compressive residual stress and is modeled by the nonlinear von Karman plate theory. A thin-layer approximation is developed for the viscoelastic layer. The stability of the bilayer and the evolution of wrinkles are studied first by a linear perturbation analysis and then by numerical simulations. Three stages of the wrinkle evolution are identified: initial growth of the fastest growing mode, intermediate growth with mode transition, and, finally, an equilibrium wrinkle state.