Comparing particle shape representations and contact models for DEM simulation of bulk cohesive behaviour
C.J. Coetzee, Otto C. Scheffler
Abstract
The Discrete Element Method (DEM) offers great potential as a design tool for the bulk simulation of cohesive systems. However, DEM simulations may require simplified particle shapes. Accordingly, the simulation of bulk dynamic, cohesive behaviour, which employs either single-sphere or multi-sphere shape replication, was compared. Additionally, the most auspicious cohesive contact models were examined, namely the Full JKR, SJKR, liquid-bridge and linear cohesive model. To this end, the elevation of a cohesive particle-bed’s centre of gravity in a rotating drum was utilised to examine the resultant cohesive behaviour. The single-spheres and multi-spheres performed similarly when replicating bulk cohesive behaviour. In addition, comparable results were observed between the simulated bulk cohesive behaviour of the Full JKR and SJKR contact models. The bulk cohesive behaviour replicated by the liquid-bridge contact model was more sensitive to the specified surface tension parameter value than the specified moisture content parameter value. The linear cohesive model could replicate bulk cohesive behaviour by only specifying a rupture force. However, including a rupture distance enhanced the bulk cohesive response, whilst the magnitude of the rupture distance was uninfluential. However, large rupture distances increased a particle’s number of contacts, which resulted in increased computational times.