Amplitude-dependent shock wave propagation in three-dimensional microscale granular crystals

Abstract

Ordered arrays of elastic spherical particles in contact, often referred to as granular crystals, have been used as a model system for understanding the dynamics of granular media and explored as a type of designer material for acoustic wave tailoring applications. Due to the Hertzian interactions between the particles, granular crystals composed of macroscale particles have been shown to support strongly nonlinear phenomena including shock and solitary waves. In this presentation, we will describe recent progress in our studies of laser-generated shock wave propagation in self-assembled three-dimensional microscale granular crystals, where adhesive forces between the particles play a major role. Specific features studied include the dependence of the shock wave velocities and absorption on excitation amplitude. Dynamic failure processes such as crater formation and spallation are also explored. The experimental measurements are compared with reduced-dimension discrete element model simulations. New under...