Experimental method for identifying constitutive parameters of rolling resistance between particles in discrete element method

A method to identify the parameters of rolling resistance between particles in the discrete element method is proposed in this paper. Experiments revealed that a free rolling particle would swing back and forth marginally before it stops. We assume that the restoring force of the swing is mainly rolling resistance. An optical experimental system was designed to obtain the rolling resistance in the DEM model. A method to identify the parameters using the time history curve of the swing is proposed. We measured the time history of the angular displacement of cylindrical samples made of rubber and aluminum. In addition, the rolling stiffness and damping coefficients were identified. The identified parameters were applied to the discrete element model to simulate the experimental process. The results show that the time-history curve of swing obtained by DEM is in good agreement with the experimental curve. This verifies that the particle swings back and forth because of rolling resistance and that the parameters of the rolling resistance model can be determined by this experimental method.