Numerical simulations of shock-induced load transfer processes in granular media using the discrete element method

Abstract

By the discrete element method (DEM), we perform numerical simulations of shock-induced load transfer processes in granular layers composed of spherical particles packed in vertical channels. In order to isolate the load transfer through the grains’ contact points from the complicated load transfer processes, we simulate the shock wave interactions with granular layers having no permeability for gas. The shock loading is achieved by applying a downward step force on the top of the granular layers. Complex, three-dimensional load transfer processes in the granular media, which are extremely difficult to understand from experiments, are visualized based on the results from the present DEM simulation. The numerical results show that highly concentrated load transfer paths, through which shock loads are transferred mainly, exist in the granular media, and that the dimensions of the container of the granular media considerably affect the shock-induced load transfer processes. From a coarse-grained representation of intergranular stress, wave-like load transfer processes are clearly observed. For relatively deep granular layers, however, the wave fronts became unclear as they propagated.