Modeling slow deformation of polygonal particles using DEM

TL;DR

This paper enhances the Discrete Element Method (DEM) for simulating slow deformation of polygonal particles by improving contact force calculations and defining a continuous contact plane, leading to better efficiency and accuracy.

Contribution

It introduces a new contact force computation approach and a continuous contact plane definition, improving DEM simulation of irregular particle dynamics.

Findings

Improved efficiency and accuracy in DEM simulations.

Determined optimal integration step limits for various materials.

Achieved continuous contact plane evolution during particle interactions.

Abstract

We introduce two improvements in the numerical scheme to simulate collision and slow shearing of irregular particles. First, we propose an alternative approach based on simple relations to compute the frictional contact forces. The approach improves efficiency and accuracy of the Discrete Element Method (DEM) when modeling the dynamics of the granular packing. We determine the proper upper limit for the integration step in the standard numerical scheme using a wide range of material parameters. To this end, we study the kinetic energy decay in a stress controlled test between two particles. Second, we show that the usual way of defining the contact plane between two polygonal particles is, in general, not unique which leads to discontinuities in the direction of the contact plane while particles move. To solve this drawback, we introduce an accurate definition for the contact plane based on the shape of the overlap area between touching particles, which evolves continuously in time.