New crushing criterion invariant to the coordination number effect in discrete element modelling

The discrete element method (DEM) is used widely to study the crushing behaviour of granular materials from a microscale perspective. However, a crushing criterion that can be suitable for triggering particle crushing for different coordination numbers (CNs) is still lacking. To develop a crushing criterion, particle crushing tests are conducted for different CNs via the DEM. Crushable spherical agglomerates are made by bonding smaller sub-spheres. Based on the results of simulations, a new crushing criterion invariant to the coordination number effect is proposed. The crushing criterion is simply expressed in terms of the three principal stresses of the particles. Furthermore, the applicability of the criterion is verified under various conditions, such as different numbers of sub-sphere, shapes of particles, microscale parameters and loading patterns. By using the new criterion, the particle strengths obtained from the single particle crushing tests can be used as the crushing strengths for the particles under multiple contact loading conditions in DEM simulations.