Improving estimates of critical time-steps for discrete element simulations

Abstract

Discrete element modelling (DEM) is a powerful software tool for simulating the interactions of granular materials. An explicit, conditionally-stable time-stepping algorithm is typically used for the discrete element method which requires a time-step, either user-specified or computed internally within the code. It is well known that too small a time-step can slow down the simulations whereas too large a time-step can lead to numerical instability. In this work we use a model example to illustrate an alternative, more exact framework for calculating the critical stable time-step for an undamped collision. This framework can be readily extended to more complex configurations.