The role of dissipation on wave shape and attenuation in granular chains

The role of dissipation on wave shape and attenuation in dry and saturated granular chains is considered experimentally and numerically. The wave dynamics in these chains includes a dissipative term based on Stoke’s drag and on a new mechanism of liquid expulsion from the developing elastic contact. The latter mechanism will be shown to be necessary for comparisons of experimental and numerical results. The dissipation of energy in the region of particle contact may serve as a model for hot-spot formation in granular materials undergoing high strain-rate deformation.The shock wave profiles in granular chains, including viscous dissipation, were analytically obtained with the long wave approximation. The critical viscosity, which describes the transition from and oscillatory to a monotonous wave profile is validated using a comparison of the analytical and discrete numerical models, which agree well with one another.