Derivation of Linearised Polycrystals from a Two-Dimensional System of Edge Dislocations

created by ponsiglio on 11 May 2018
modified by fanzon on 01 Aug 2020

[BibTeX]

Published Paper

Inserted: 11 may 2018
Last Updated: 1 aug 2020

Journal: SIAM Journal on Mathematical Analysis
Volume: 51
Number: 5
Pages: 3956-3981
Year: 2019
Doi: https://doi.org/10.1137/18M118726X

ArXiv: 1805.04484 PDF

Abstract:

In this paper we show the emergence of polycrystalline structures as a result of elastic energy minimisation. For this purpose, we introduce a variational model for two-dimensional systems of edge dislocations, within the so-called core radius approach, and we derive the $\Gamma$-limit of the elastic energy functional as the lattice space tends to zero. In the energy regime under investigation, the symmetric and skew part of the strain become decoupled in the limit, the dislocation measure being the curl of the skew part of the strain. The limit energy is given by the sum of a plastic term, acting on the dislocation density, and an elastic term, which depends on the symmetric strains. Minimisers under suitable boundary conditions are piece-wise constant antisymmetric strain fields, representing in our model a polycrystal whose grains are mutually rotated by infinitesimal angles.

Keywords: dislocations, Variational methods, polycrystals