Shape representation of axi-symmetrical, non-spherical particles in discrete element simulation using multi-element model particles

A new method of representing non-spherical, smooth-surfaced, axi-symmetrical particles in discrete element (DE) simulation using model particles comprising overlapping spheres of arbitrary size whose centres are fixed in position relative to each other along the major axis of symmetry of the particle is presented. Contact detection and calculation of force-deformation and particle movement is achieved using standard DE techniques modified to integrate the behaviour of each element sphere with that of the multi-element particle to which it belongs. The method enables the dynamic behaviour of particles of high aspect ratio and irregular curvature (in two dimensions) to be modelled. The use of spheres to represent a particle takes advantage of the computational speed and accuracy of contact detection for spheres, which should make the method comparable in computational efficiency to alternative schemes for representing non-spherical particles.