Linking Discrete Dislocations and Molecular Dynamics in 3D: a Start

摘要: Many phenomena in crystalline metals such as friction, nano-indentation and ductile fracture are plasticity-driven poorly understood. The physical complexity is further increased by the inherently multiscale nature of contact [1]. This study aimed at a realistic numerical treatment plasticity during nanoscale scratching metal. principal mechanism dislocation nucleation motion. Nucleation an atomic phenomenon often localised interfaces, crack tips, etc., while motion microscale occurring within grains polycrystalline microstructure [2]. molecular dynamics (MD) method able to accurately predict nucleation, however time length scale limitations [3] MD do not permit for description entire networks. latter computed much more efficiently [4] with discrete (DD) where details atomistic core eliminated from consideration. We present extend 3D coupled atomistics dislocations (CADD) [5, 6, 7]. To date, CADD has been restricted plane strain problems straight disloca- tions. In CADD, solid split into two regions (e.g. Figure 1(a)): region, highly non-linear deformations (i.e. nucleation) complex defect interactions expected that require resolution, DD plastic behaviour due can be lower cost. couple these regions, MD/DD interface (see 1(b)) uses layer region approaching detected fictitious pad atoms serve boundary conditions region. An iterative solution permits tracking lines span minimal spurious forces coupling. apply coupling scheme simplest problem - edge under uniform applied shear. results will used show capabilities method, guide extension problems.