An extended Greenwood‐Williamson modelbased normal interaction law for discrete element modelling of spherical particles with surface roughness

Abstract

Summary The current work aims to develop an improved random normal interaction law based on an extended Greenwood‐Williamson (GW) model for spherical particles with surface roughness in the discrete element modelling of particle systems. The extended GW model overcomes some theoretical defects of the classic GW model when incorporated into the discrete element framework. Based on 2 nondimensional forms in which only 2 surface roughness parameters are involved, an empirical formula of the improved interaction law is derived by the curve‐fitting technique. The resulting interaction law is incorporated into discrete element modelling to investigate the mechanical response of particle systems with different surface roughness. Numerical simulations are performed to model 1‐dimensional and 3‐dimensional compression tests to explore the macro and micro characteristics of granular particles with surface roughness. The results show that surface roughness makes the initial packing of a particle assembly looser and has a greater influence on looser packed samples as expected, but an assembly with moderate roughness may exhibit a higher strength. The limitations of the current development are also highlighted.

Extended Greenwood–Williamson Models for Rough Spheres

“…This is, however, not true for most practical problems where a certain degree of uncertainties is always involved, and therefore traditional deterministic approaches may not be able to treat real problems adequately. A stochastic discrete element modelling methodology which is intended to consider the influence of inherent uncertainties on particulate systems has been developed in our previous work [1,2].…”

“…As currently used normal contact laws in DEM, such as the linear and the Hertz contact models, are intended for contact between smooth particles, it may be significant if surface roughness can be included in contact interaction laws in a statistic sense. A first attempt has been made towards this goal in our previous work [1] where a novel random normal interaction law has been proposed, and its application has been demonstrated in [2].…”