Investigation of multi-sphere models in DEM simulations of granular flow-comparison with smooth ellipsoids

Abstract

Simulation of dry non-cohesive visco-elastic granular materials by the Discrete Element Method (DEM) is considered. This work addresses the problem of particle shape. The Multi-Sphere (MS) approach to approximation of the smooth ellipsoidal particle with the increasing number of sub-spheres is studied by solving a piling problem and qualitative and quantitative comparison of both models is presented. Based on the simulation results obtained, it could be stated that MS model approximates the smooth particle within the limits of the appropriate tolerance. A macroscopic MS model possesses, however, different interaction behaviour of particles on microscopic level. It has been demonstrated how artificial increase of the friction coefficient is related to the number of sub-spheres.