Dislocation dynamics modeling in confined volumes

When plastic deformation takes place in specimens or volumes with dimensions on the order of micrometers, the discrete nature of dislocations can no longer be ignored and continuum plasticity breaks down. The present paper discusses a three-dimensional dislocation dynamics method that allows the study of plastic deformations in micron-sized specimens. The approach involves two main parts: (i) plastic Row is modeled through a discrete dislocation dynamics simulation; (ii) a finite element model is used to incorporate traction or displacement boundary conditions on the specimen. Elementary validations of the dislocation discretization are discussed which have been performed for Frank-Read sources and for circular loops in infinite space. The incorporation of boundary conditions is illustrated for a free-standing thin film, with due emphasis on the treatment of dislocation loops that have partly glided out of the body.