Analysis of shear shock waves in soft materials: From periodic elastic laminates and fibre-reinforced composites to molecular chain networks

Abstract

We investigate the effect of microstructure and molecular length-scale structures on the formation of shear shock waves in soft materials. We consider (i) soft materials with layered microstructures, (ii) transversely isotropic fibre-reinforced composites (FC), as well as (iii) molecular chain networks, using homogenised energy density functions at the continuum scale. Critical conditions for the formation of shear shocks are found analytically for laminates and FCs, and are shown to depend only on the angle between the initial orientation direction and the applied load. We elucidate the effects of the microstructural material parameters on the shock formation distance. Our results show that increased stiffness ratio and volume fraction of fibres decreases the shock formation distance. The analysis of molecular chain networks indicates that an increase in the entanglement increases the critical shock formation distance. We also highlight that by an appropriate choice of loading and material parameters, shock formation can be avoided, providing guidance for design of protective materials and structures.