Basic Description of DEM

Abstract

Discrete Element Method (DEM) is a numerical method that considers the mutual interactions of discrete particles in contact and enables evaluations of mutual force interactions. This method requires equations of translation movement and equations of rotation movement for each particle. The basic model is solved using the linear visco-elasticity (Fig. 2.1). This calculation uses the parallel connection of the damper with spring (Voight model) as a substitution scheme for each contact, which incorporates rolling and shear friction. More complex calculations also use other inputs, e.g., plastic deformation. In these models, the components of normal forces are calculated according to the theory of Herz’s contacts [1]. In the kinetic Eq. (2.1), there are also the tangential forces that were defined by Mindlin [2] and Mindlin - Deresiewicz [3]. The basis of these frictional tangential forces is the Coulomb law of the friction model, which is explained in Cundall and Strack [4]. The equations also include the damper components of normal and tangential force for which the coefficient of damping relates to the coefficient of restitution. These parameters were explained in Tsuji, Tanaka, and Ishida [5].