Continuum mechanics at the atomic scale: Insights into non-adhesive contacts using molecular dynamics simulations

Classicalmolecular dynamics (MD) simulations were performed to study non-adhesive contact at the atomic scale. Starting from the case of Hertzian contact, it was found that the reducedYoung's modulusE* for shallow indentations scales as a function of, both, the indentation depth and the contact radius. Furthermore, the contact of two representativerough surfaces was investigated: one multi-asperity, Greenwood-Williamson-type (GW-type) rough surface  — where asperities were approximated as spherical caps — and a comparable randomly rough one. The results of theMD simulations were in agreement for both representations and showed that the relative projected contact areasArpc were linear functions of nominal applied pressures, even after the initiation ofplastic deformation. When comparing theMD simulation results with the corresponding continuum GW and Perssonmodels, both continuummodels were found to overestimate the values ofArpc relative to theMD simulation results.

Source: Journal of Applied Physics - December 1, 2016 Category: Physics Authors: Soheil Solhjoo and Antonis I. Vakis Source Type: research