Atomistic determination of stress fields in samples with defects

Abstract

The main goal of the study is the atomistic determination of the static stress-strain state at the crack tip in isotropic and anisotropic linearly elastic materials by the molecular dynamics method implemented in the open source LAMMPS (Large-scale Atomistic/Molecular Massively Parallel Simulator). An extensive class of computational experiments has been carried out for a single-crystal copper specimen with a central crack in the LAMMPS. The circumferential distributions of the stress tensor components obtained by molecular dynamics are compared with the angular distributions of brittle fracture continuum mechanics, i.e. with Williams’ analytical solution to the problem of an infinite plate loaded with a central crack in a linearly elastic isotropic material. The comparison of the angular distributions of the stress tensor components gained in the framework of atomistic modeling and the angular distributions obtained from the classical solution of continuum mechanics has shown that, at the nanoscale level, the stress fields are in good agreement with their macroscopic values.