Multi-sphere ellipsoidal particles in dem simulations of piling problem

Abstract

The multi-sphere (MS) approximation approach of the 3D axi-symmetric ellipsoidal particle is considered. An algorithm for hierarchical description of ellipsoid is suggested.Non-cohesive frictional visco-elastic MS ellipsoidal particle model is developed and implemented into the original DEM code . Performance of the MS approach is examined by solving a piling problem. A set of 1000 mono-sized ellipsoidal particles characterized by the aspects ratio s=2.35 is employed for simulation. Concentrated sequential particle piling was considered and a repose angle is studied. Approximation effect is investigated by the increased number of spheres ranging from 3 to 17. The deviation of a multi-sphere shape from ellipsoid at the paticle level is evaluated by the suggested shape distortion factors. It has been found, that convergence of repose angle obtained by MS model to ellipsoidal model when the number of spheres increases , has similar tendency as that of variation of distortion factors.