Multiscale modeling of three dimensional discrete dislocation dynamics and boundary element method and its application to nanoindentation problem

Tsuru, Tomohito   ; Shibutani, Yoji*

In the nano-plastic deformation, material properties cannot be described by the average rate of dislocation behavior, and it becomes increasingly necessary to trace individual motion of dislocations. Molecular dynamics (MD) is one of the most effective methodologies to obtain dislocation motion. However, MD simulation depends on the computer power so strongly that it is difficult to treat mesoscopic behavior including collective dislocation motion. Discrete dislocation mechanics (DD) has a unique ability to treat dislocation motion. In the present paper, we construct a combined approach including both DD and the boundary element method, and succeed in representing the stress field of dislocation in the vicinity of traction free surface. Finally, we apply this model to the nanoindentation problem and found the relationship between displacement burst and collective dislocation motion.