Elastic waves in particulate glass-rubber mixtures

We investigate the propagation of waves in dense static granular packings made of soft and stiff particles subjected to hydrostatic stress. Physical experiments in a triaxial cell equipped with broadband piezoelectric wave transducers have been performed at ultrasound frequencies. The time of flight is measured in order to study the combined effect of applied stress and rubber content on the elastic properties of the mixtures. The bulk stiffness deduced from the wave speed is nonlinear and non-monotonic with the increasing percentage of rubber with a more prominent effect at higher pressures. Moreover, in the frequency domain, a spectral analysis gives insights on the transition from a glass- to a rubber-dominated regime and the influence of rubber particles on the energy dissipation. Mixtures with rubber content below 30% show enhanced damping properties, associated with slightly higher stiffness and lighter weight.

Automated summary

The study investigates the wave propagation and elastic properties of waves in dense granular packings made of soft and stiff particles, emphasizing the effects of applied stress and rubber content on the mixtures. It highlights the transition in frequency domain from glass- to rubber-dominated regimes and the influence of rubber particles on energy dissipation. Mixtures with rubber content below 30% exhibit enhanced damping properties.