Pulse mitigation by a composite discrete medium

The strongly nonlinear interaction between elements in discrete materials (e.g., grains in granular media) is responsible for their unique wave propagation properties. The paper will present an experimental observation of impulse energy confinement and the resultant disintegration of shock and solitary waves by discrete materials with strongly nonlinear interaction between elements. Experiments and numerical calculations will be presented for alternating ensembles of high-modulus vs orders of magnitude lower-modulus chains of spheres of different masses. The trapped energy is contained within the “softer” portions of the composite chain and is slowly released in the form of weak, separated pulses over an extended period of time. This effect is enhanced by using a specific group assembly and a superimposed force