  A novel implementation of the dislocation flux boundary condition is
presented. In this implementation, the line continuity of the individual
dislocation loops in a periodic representative crystal volume (RVE) is enforced
as they encounter the boundary of the RVE. A dual topological description has
been utilized for representing dislocation line kinematics in two equivalent
spaces of the deforming crystal, namely, the RVE and the unbounded bulk crystal
spaces. The former describes the motion of the dislocations in the simulated
crystal volume whereas the latter represents the motion of dislocations in an
infinite space containing all replicas of the RVE. A mapping between the two
spaces forms the basis of the implementation of flux boundary condition. The
implementation has been carried out in a state-of-art dislocation dynamics
research tool called the Mechanics of Defect Evolution Library (MoDELib). The
implementation details are discussed in the context of statistical homogeneity
of bulk crystals undergoing macroscopically homogeneous plastic deformation.
Some test cases are presented and discussed to establish the accuracy of the
proposed approach. By using this approach, it has been observed that the
boundary nodes associated with dislocation segments bear no relevance in the
motion of the dislocation segments from the standpoint of bulk crystal
plasticity modeling throughout the deformation history of the crystal.
