Contact Modeling in the Discrete Element Method

Abstract

The discrete element method (DEM) is a wide family of numerical methods for discrete and discontinuous modelling of materials and systems which can be represented by a large collection of particles (discrete elements). The DEM assumes that the discrete elements interact with one another by contact forces. This chapter presents basic aspects of contact modeling in the DEM. The main assumptions, theoretical formulation and numerical algorithm of the DEM are presented. In this work, the DEM formulation employing spherical particles and the soft-contact approach is considered. Basic contact models for the particle interaction are reviewed. Elementary contact mechanisms, including elasticity, plasticity, damping, friction and cohesion are discussed. Selected contact models combining these effects are described. Their performance in modelling single dynamic or quasi-static contact events is analysed. The analysis is focused on the evolution of contact forces during single collisions. Although the force-type interaction is mainly discussed, the moment-type interaction is also introduced. Formulation of the DEM contact taking into account thermal effects as well as thermomechanical coupling finishes this review.