Adhesive wear with a coarse-grained discrete element model

TL;DR

This paper introduces a coarse-grained discrete element method (DEM) model to simulate adhesive wear, capturing key mechanisms observed in molecular dynamics (MD) while enabling larger scale simulations at reduced computational cost.

Contribution

The paper presents a DEM approach that reproduces MD-observed adhesive wear mechanisms, allowing larger and more scalable simulations.

Findings

DEM successfully replicates MD single asperity wear results.

DEM simulations operate at larger scales with lower computational cost.

The model accurately captures elastic and fracture properties of the material.

Abstract

The use of molecular dynamics (MD) simulations has led to promising results to unravel the atomistic origins of adhesive wear, and in particular for the onset of wear at nanoscale surface asperities. However, MD simulations come with a high computational cost and offer access to only a narrow window of time and length scales. We propose here to resort to the discrete element method (DEM) to mitigate the computational cost. Using DEM particles with contact and cohesive forces, we reproduce the key mechanisms observed with MD, while having particle diameters and system sizes an order of magnitude higher than with MD. The pairwise forces are tuned to obtain a solid with reasonably approximated elastic and fracture properties. The simulations of single asperity wear performed with MD are successfully reproduced with DEM using a range particle sizes, validating the coarse-graining procedure. More complex simulations should allow the study of wear particles and the evolution of worn surfaces in an adhesive wear context, while reaching scales inaccessible to MD.