Proceedings of The Royal Society A - LaTeX Template.zip from 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.本研究探究了受静水应力作用、由软质与硬质颗粒构成的致密静态颗粒堆积体中的波传播特性。本研究借助配备宽带压电波换能器（piezoelectric wave transducers）的三轴压力室，开展了超声频段的物理实验。通过测量飞行时间（time of flight, ToF），旨在探究施加应力与橡胶颗粒含量对混合体系弹性特性的联合影响。由波速推导得到的体积刚度（bulk stiffness），随橡胶颗粒占比提升呈现非线性且非单调的变化规律，且在较高压力下该效应更为显著。此外，在频域范围内开展的频谱分析，可揭示从玻璃质颗粒主导态至橡胶颗粒主导态的转变过程，以及橡胶颗粒对能量耗散的影响机制。橡胶颗粒占比低于30%的混合体系，其阻尼特性得到增强，同时具备略高的刚度与更轻的质量。