A Study of Elastic Waves and Hopkinson Bar Effect Using Granular Model
Toshifumi MATSUOKA, Harushige KUSUMI, Zentaro WAKATSUKI and Yuzuru ASHIDA
Abstract:The technologies of the numerical analysis made remarkable progress to understand the geoscience phenomena. In these approaches, however, the subsurface has been modeled by a continuum medium and the finite difference method, finite element method or boundary element method is adopted to solve the governing equations. Therefore, it is hard to treat the discontinuous phenomena. We applied a granular model to represent the bedrock medium to handle this problem. In this paper, we introduced the normal and shear springs to connect particles in granular model and this leads the Poissonfs ratio of the medium changeable. We simulated the elastic wave propagation phenomena and also the Hopkinson bar phenomena in the granular model. The simulation results show this approach is quite useful for analyzing the fracturing and/or discontinuity phenomena in the subsurface. Key Words:Granular model, Continuum model, Elastic waves, Poisson's ratio, Hopkinson bar