Simulations of surface stress effects in nanoscale single crystals

TL;DR

This paper presents a combined molecular dynamics and finite element simulation approach to analyze surface stress effects in nanoscale single crystals, specifically copper with nanovoids, incorporating surface effects into stress calculations.

Contribution

It introduces a novel methodology that integrates surface effects into finite element models using elastic properties from molecular dynamics, enhancing analysis of nanoscale surface phenomena.

Findings

Developed a computationally efficient stress calculation method.

Successfully incorporated surface effects into finite element analysis.

Applicable to studying nanoscale surface stress phenomena.

Abstract

Onset of vacuum arcing near a metal surface is often associated with nanoscale asperities, which may dynamically appear due to different processes ongoing in the surface and subsurface layers in the presence of high electric fields. Thermally activated processes, as well as plastic deformation caused by tensile stress due to an applied electric field, are usually not accessible by atomistic simulations because of long time needed for these processes to occur. On the other hand, finite element methods, able to describe the process of plastic deformations in materials at realistic stresses, do not include surface properties. The latter are particularly important for the problems where the surface plays crucial role in the studied process, as for instance, in case of plastic deformations at a nanovoid. In the current study by means of molecular dynamics and finite element simulations we analyse the stress distribution in single crystal copper containing a nanovoid buried deep under the surface. We have developed a methodology to incorporate the surface effects into the solid mechanics framework by utilizing elastic properties of crystals, pre-calculated using molecular dynamic simulations. The method leads to computationally efficient stress calculations and can be easily implemented in commercially available finite element software, making it an attractive analysis tool.