A thermodynamically consistent theory of stress-gradient plasticity

TL;DR

This paper introduces a thermodynamically consistent stress-gradient plasticity model for single crystals, extending size-dependent plasticity theories with a novel framework that is validated through numerical torsion experiments.

Contribution

It presents the first thermodynamically consistent stress-gradient plasticity model embedded in single-crystal plasticity, advancing the theoretical foundation of size-dependent plastic behavior.

Findings

The model captures size effects in crystal plasticity.

Numerical simulations show agreement with disequilibrium density models.

The framework enhances understanding of stress-gradient influences.

Abstract

As an extension to strain-gradient models of size-dependent plastic behaviour, this work proposes a model for a stress-gradient theory. The model is distinguished from earlier works on the topic by its being embedded in a thermodynamically consistent framework. The development is carried out in the context of single-crystal plasticity, and draws on thermodynamically consistent models for single-crystal conventional and strain-gradient plasticity. The model is explored numerically using the example of torsion of a thin wire comprising a face centred cubic crystal, and its behaviour compared with that based on a recent disequilibrium density model of size-dependent plasticity.