(75f) Qualitative Assessment of the Influence of Coordination Number on Crushing Strength Using Dem

The research explores the influence of coordination numbers on the crushing strength of grains using DEM. DEM simulations were conducted using a two-dimensional Particle Flow Code program (Itasca, 2005). Models of grains were prepared by bonding together micro-spheres using parallel bonds similar to the approach utilized by Robertson (2000). Grain crushing in the Brazilian test was investigated. While the strength of particles is often measured using conventional Brazilian tests with two straight loading platens, in natural environments particles are surrounded by more than two neighboring particles. In this paper we study the effect of curvature as well as coordination number on the measured ultimate load resistance. The paper shows how the crushing strength increases as the coordination number increases or decreases as the curvature of the loading particles increases. Results from this 2D study provide some qualitative data on the crushing phenomena observed in disks that are packed together. The paper discusses the anisotropic nature of fracture propagation throughout the grain as a function of different numerical strategies in the process of the grain building. It is noticed that as the coordination number increases and a state of isotropic compression is approached, there is no distinct crushing strength that can be observed. This is consistent with findings by Tsongui et al. (1999) during their experimental observations on crushing of molding plaster disks.