Anomalous energy dissipation in molecular-dynamics simulations of grains: The ‘‘detachment’’ effect

We study models for granular materials using both molecular-dynamics (MD) and event-driven (ED) methods. In the MD simulations we implement linear as well as nonlinear interaction laws. In the case of multiparticle interactions, we find that MD calculations lead to an anomalous energy loss. In this paper we elucidate this effect and the conditions under which it appears.