Elastic-plastic behaviour of contacting layered spherical particles

Abstract

Most of DEM simulations employ homogeneous particles. However, in reality, many particles of natural and industrially produced materials are covered by a layer possessing different properties. Normal contact behaviour of two elastic-plastic spheres was investigated by the Finite Element Method (FEM) for a wide range of yield stresses and hardening. The particle consists of a relatively stiff elastic surface layer and a relatively soft elastic-plastic nucleus. Assuming axial symmetry, only a quarter of each sphere is considered in the FEM model. Problem-oriented user-controlled mesh generator is suggested for radially shaped and segmented structure of the FE mesh, working in the ANSYS environment. Contact force-displacement relationship was the main target of the FEM analysis. Simulation results are presented in the form of the forcedisplacement power law suitable for DEM applications, where the influence of the layer, geometric stiffing and plasticity are considered to be the basis of the homogeneous Hertz solution. Contact pressures are also considered to demonstrate the effect of plasticization.