Internal variable modelling of wave propagation in laminates with nonlinearly elastic constituents

The phenomena of wave propagation normal to the layers of a periodically layered elastic media comprised of nonlinear elastic constituents is modeled by employing an internal variable theory. Using the model a fourth-order nonlinear partial differential equation is derived for the evolution of the mean displacement in the laminate; properties of the solutions of the relevant evolution equation are then studied both in a neighborhood of the precursor wave as well as in a neighborhood of a characteristic traveling with the main or composite wave speed.