Wave propagation in force chains

Abstract

We present numerical simulations of acoustic wave propagation in disordered granular media. Small amplitude oscillations of compressed static configurations of frictionless spherical grains are analyzed. Force chains, while important for the static properties of the granular assemblies, do not play a dominant role in transmitting acoustic waves according to our observations. Reasons include that the stiffness network is less widely distributed than the force network, and the nearby grains are coupled relatively strongly to grains in the force chain. The transmitted acoustic signal can be decomposed to an initial cycle and a more noisy tail, similarly to related experiments.