Continuum simulation of dislocation dynamics: predictions for internal friction response

The amplitude dependent mechanical loss due to bowing of an idealized Frank-Read source is studied using both simulation and analytical techniques. Dislocations are modeled within isotropic elasticity theory, and are assumed to be in the over-damped limit. The dynamics incorporated in the model are tested directly, by comparison with the exact solution to the linearized isotropic elasticity theory of the mechanical losses. The model is then applied to the study of the mechanical losses from two coupled dislocations. It is concluded that the implemented dislocation dynamics method represents an accurate solution to the initially stated problem, that the elastic string model often employed to model losses is inadequate, and that dislocation interactions may alter substantially the dislocation component of the spectrum observed during internal friction experiments. (C) 2002 Elsevier Science B.V. All rights reserved.