Concurrent adaptive mass-conserving comminution of granular materials using rigid elements

Abstract

The process of comminution, occurring during compaction and impact on granular media, affects dramatically the mechanical response of the materials. The adoption of rigid particles—common in DEM simulations—fails to reproduce accurately the grain fracture. The often-adopted solutions of replacing a broken particle with a cluster of either overlapping or non-overlapping spheres have the main drawback of inducing, respectively, repulsive spurious forces that badly affect the inter-particles contact or an undesirable loss of mass. This paper presents a novel method to overcome the issues of mass loss without imposing overlapping of the particles. When a failure condition is reached, the domain is decomposed using a Laguerre-Voronoi tessellation approach. A dense agglomerate of tangent, non-overlapping particles, generated with an efficient geometrical packing algorithm, fills the polyhedral cell containing the failed particle. Since the polyhedral cell is, by construction, bigger than the failed particle, the approach developed allows for a drastic—if not complete—reduction of the mass loss within a time efficient, concurrent simulation of the comminution process.