Dislocation dynamics simulations of the interaction between a short rigid fiber and a glide circular dislocation pile-up

Abstract

This paper presents dislocation dynamics simulations of the interaction of a circular dislocation pileup with a short rigid fiber as occurs, for example, in metal–matrix composites. The pile-up is composed of glide dislocation loops surrounding the fiber. Here, this problem is treated as a boundary value problem within the context of dislocation dynamics. The proper boundary condition to be enforced is that of zero displacements at the fiber–matrix interface. Such a condition is satisfied by a distribution of image rectangular dislocation loops meshing the fiber's surface. This treatment is similar to crack modeling using distributed dislocations and falls under the category of “generalized image stress analysis”. The unknown in this problem is the Burgers vectors of the surface loops. Once those are found, the Peach–Koehler (PK) force acting on the circular dislocation loops, and emulating the fiber–dislocation interaction, can be determined and the dynamical arrangement of the circular pile-up evolves naturally from conventional dislocation dynamics analysis.