Effect Geometric Detail on the Outcome of DEM Simulations with Polyhedral Particles

The discrete element method is often used in modelling of a variety of problems in granular materials. The shape and asperities of a particle affects the simulation outcome due to differences in collision behaviour. The differences can be significantly different for polyhedral particles. In this research, 3D scanning of rock fragments at various levels of geometric detail was used to determine the influence asperities and geometric detail. These particles were used in simulating the impact with a solid block and metrics were collected, including the time of initial contact, duration of contact and time of maximum force along with the magnitude of forces and impulse. The computational effort required was measured as well. It was found that the changes in geometry result in alteration of a particle’s extent, volume and surface area, leading to differences in the initial contact time and duration. The decreasing geometric detail yields differences up to 30% on average for a single collision alone. The particle resolution shows a lesser influence on the magnitude of the contact force and impulse. It can be concluded that about a few hundred elements are sufficient in representing a particle when considering the computational costs.