  The formation of periodic wrinkles in soft layered materials due to
mechanical instabilities is prevalent in nature and has been proposed for use
in multiple applications. However, such phenomena have been explored
predominantly in quasi-static settings. In this work, we measure the dynamics
of soft elastomeric blocks with stiff surface films subjected to high-speed
impact, and observe wrinkles forming along with, and riding upon, waves
propagating through the system. We analyze our measurements with
large-deformation, nonlinear visco-hyperelastic Finite Element simulations
coupled to an analytical wrinkling model. The comparison between the measured
and simulated dynamics shows good agreement, and suggests that inertia and
viscoelasticity play an important role. This work encourages future studies of
the dynamics of surface instabilities in soft materials, including
large-deformation, highly nonlinear morphologies, and may have applications to
areas including impact mitigation, soft electronics, and the dynamics of soft
sandwich composites.
