Wrinkles Riding Waves in Soft Layered Materials

TL;DR

This study investigates the dynamic formation of wrinkles in soft layered materials under high-speed impact, revealing the roles of inertia and viscoelasticity through experiments and simulations, with implications for impact mitigation and soft electronics.

Contribution

It introduces a combined experimental and simulation approach to study dynamic wrinkle formation in soft materials under impact, highlighting the importance of inertia and viscoelastic effects.

Findings

Good agreement between experiments and simulations

Inertia and viscoelasticity significantly influence wrinkle dynamics

Potential applications in impact mitigation and soft electronics

Abstract

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.