Coupling Phase Field Crystal and Field Dislocation Mechanics for a consistent description of dislocation structure and elasticity
Couplage de de champ de phase cristalline et des dislocations de champ pour une description cohérente de la structure des dislocations et de l'élasticité
Résumé
This work addresses differences in predicted elastic fields created by dislocations
either by the Phase Field Crystal (PFC) model, or by static Field Dislocation
Mechanics (FDM). The PFC order parameter describes the topological content of the lattice, but it fails to correctly capture the elastic distortion. In contrast, static FDM correctly captures the latter but requires input about defect cores. The case of a dislocation dipole in two dimensional, isotropic, elastic medium is studied, and a weak coupling is introduced between the two models. The PFC model produces compact and stable dislocation cores, free of any singularity, i.e., diffuse. The PFC predicted dislocation density field (a measure of the topological defect content) is used as the source (input) for the static FDM problem. This coupling allows a critical analysis of the relative role played by configurational (from PFC) and elastic (from static FDM) fields in the theory, and of the consequences of the lack of elastic relaxation in the diffusive evolution of the PFC order parameter.
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