Kamyar M. Davoudi

Abstract:

Many important properties of crystalline materials are controlled by the dislocation core. There have been many attempts to remove the elastic field singularities at the dislocation core. Three of the most common methods for regularizing the elastic fields are: (1) considering a cutoff parameter, (2) spreading the Burgers vector in all directions as proposed by Cai et al., (2006. A non-singular continuum theory of dislocations. J. Mech. Phys. Solids, 54, 561–587), and (3) using gradient elasticity. Each of these methods requires an extra parameter with the dimension of length. We show that these characteristic length parameters can significantly affect the results of the discrete dislocation simulations. By comparing with the results of atomistic simulations, we show how the core energy should be included if an arbitrary constant is chosen for the characteristic parameters for each of these three nonsingular theories of dislocations.