Adhesive wear with a coarse-grained discrete element model

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 of 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. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

The use of molecular dynamics (MD) simulations and the discrete element method (DEM) can unravel the atomistic origins of adhesive wear. MD simulations have a high computational cost and are limited to a narrow time and length scale, while DEM can reduce the computational cost and have larger particle diameters and system sizes. Single asperity wear simulations performed with MD can be successfully reproduced with DEM, validating the coarse-graining procedure. DEM allows for more complex simulations and reaching scales inaccessible to MD in the context of adhesive wear.