Modification of the spherical particle spring-damping contact model from contact velocity dependent restitution coefficients

The most common granular flow Discrete Element Method (DEM) simulation contact model is the spring-damping model, which typically uses constant restitution coefficients to estimate the model damping coefficient. The predicted rebound velocities are thus pre-determined by the ad hoc restitution coefficient setting. Considering the fact that the coefficient of restitution is contact velocity-dependent and event driven, we advance the spring-damping model using three contact velocity-dependent restitution coefficient approaches. We show that the spring-damping model using a new restitution coefficient approach derived from the model of Walton & Braun (1986) gives good rebound velocity predictions over a range of contact velocities for four spherical particles of different hardness.