Numerical simulation of model problems in plasticity based on field dislocation mechanics

TL;DR

This paper develops an efficient numerical scheme using high-resolution Godunov-type solvers to simulate dislocation-mediated plasticity within the Field Dislocation Mechanics framework, validated through simplified model problems.

Contribution

It introduces a novel numerical method based on Godunov-type solvers for the evolution problem in FDM, enhancing simulation efficiency and accuracy.

Findings

Successfully simulated dislocation annihilation and loop expansion.

Applied FDM to microstructure problems under mechanical loading.

Validated the numerical scheme with simplified layer models.

Abstract

The aim of this paper is to investigate the numerical implementation of the Field Dislocation Mechanics (FDM) theory for the simulation of dislocation-mediated plasticity. First, the mesoscale FDM theory of Acharya and Roy (2006) is recalled which permits to express the set of equations under the form of a static problem, corresponding to the determination of the local stress field for a given dislocation density distribution, complemented by an evolution problem, corresponding to the transport of the dislocation density. The static problem is solved using FFT-based techniques (Brenner et al., 2014). The main contribution of the present study is an efficient numerical scheme based on high resolution Godunov-type solvers to solve the evolution problem. Model problems of dislocation-mediated plasticity are finally considered in a simplified layer case. First, uncoupled problems with uniform velocity are considered, which permits to reproduce annihilation of dislocations and expansion of dislocation loops. Then, the FDM theory is applied to several problems of dislocation microstructures subjected to a mechanical loading.