Determination of the maximum time step for DEM simulation.

To study the properties of granular materials during their pressing, granulation, and transportation, the discrete element method (DEM – Discrete element method) simulation is used. To verify the software implementation of the method, as well as to choose the time step of the calculation, the presence of reliable test cases is required. An analytical solution is found for determining the time step at which the calculation instability is achieved. The instability emerges due to the fact that the period of particle oscillations is equal to the time step. A scheme is proposed for determining the time step at which there is an instability of the program calculation that uses DEM. The time step calculation obtained analytically and using the program are compared. In order to improve the performance of a computer program, a computational approach is proposed in which the elastic modulus decreases and the time step increases. The dependence of the time step on the elastic modulus and the coefficient of restitution is shown. [ABSTRACT FROM AUTHOR]