Spalling of a one-dimensional viscoelastic bar induced by stress wave propagation

Abstract

As a stress wave propagates in rock, the amplitude of the stress wave will attenuate, and the waveform will dissipate, which can be equivalently characterized by the stress wave propagation in a viscoelastic material. The stress wave propagation may induce rock damage when the stress is greater than the rock strength. In this study, viscoelastic wave propagation in rock and the damage and failure process of rock induced by viscoelastic wave propagation, which are usually examined separately in existing theoretical and numerical models, were investigated under a unified framework. Based on viscoelastic damage theory and the theory of stress wave propagation in a one-dimensional viscoelastic bar, theoretical equations for spalling fracture of a viscoelastic bar were obtained. Then, the numerical model implemented by the one-dimensional wave propagation program was validated by reproducing the dynamic spalling of green sandstone bar; after that step, the program was employed to study the behavior of viscoelastic bar spalling. Based on the numerical simulation, the condition, position and time of the dynamic spalling induced by quarter sine wave propagation in the viscoelastic bar were examined, and the influence of the amplitude and frequency of the quarter sine wave and the viscosity coefficient and length of the viscoelastic bar on the spalling were quantified.