Instability of a compressed elastic film on a viscous layer (Q1858682)

In many film/substrate systems, the film is in a state of biaxial compression. Instability and failure modes of such systems have been observed. A film with a large unbonded flaw can buckle away from the substrate under the compressive stress and the buckle then causes the flaw to spread if the compressive stress is large enough. A flat, compressed elastic film of a viscous layer is unstable. The film can form wrinkles to reduce the elastic energy. A linear perturbation analysis is performed to determine the critical wave number and the growth rate of the unstable modes.