The Interaction of a Circular Dislocation Pile-up with a Short Rigid Fiber: a 3-D Dislocation Dynamics Simulation

Abstract

ABSTRACTThis paper presents a dislocation dynamics simulation of the interaction of a circular dislocation pile-up with a short rigid fiber, say as in metal-matrix composites. The pile-up is composed of glide dislocation loops surrounding the fiber. This problem is treated here as a boundary value problem within the context of dislocation dynamics. The proper boundary condition to be enforced is that of no or zero elastic displacements at the fiber's surface. Such a condition is satisfied by a distribution of rectangular dislocation loops, acting as sources of elastic displacements, meshing the fiber's surface. Such 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 force acting on the circular dislocation loops, and emulating the fiber's presence, can be determined and the dynamical arrangement of the circular pile-up evolves naturally from traditional dislocation dynamics analysis.