Verification of a multiscale surface stress model near voids in copper under the load induced by external high electric field

摘要

In the current study we use a model of surface stress for finite element method calculations to complement existing bulk stress models. The resulting combined model improves the accuracy of stress calculations near nanoscale imperfections in the material. We verify the results by simulating differently-shaped voids in single crystal copper both with FEM and with molecular dynamics, and compare the resulting stress distributions. The compared results agree well within small uncertainties, indicating that the implemented surface stress model is able to capture all the major features of the stress distributions in the material. Discrepancies occur near surfaces, where the crystal faces were not defined explicitly in the model. The fast and accurate FEM calculations can be used to estimate the stress concentration of specific extended defects, such as voids, while studying the dislocation-mediated mechanisms near these defects in the presence of external stresses by atomistic techniques.