Strain localization and anisotropic correlations in a mesoscopic model of amorphous plasticity

TL;DR

This paper introduces a two-dimensional mesoscopic model for amorphous plasticity, revealing how local reorganizations and sample preparation influence strain localization and anisotropic correlations during deformation.

Contribution

It presents a novel mesoscopic simulation framework capturing complex localization and correlation phenomena in amorphous materials, emphasizing the role of initial sample preparation.

Findings

Localization depends on sample preparation.

Anisotropic strain correlations are quantitatively characterized.

Model reproduces experimental and atomistic features of amorphous plasticity.

Abstract

A mesoscopic model for shear plasticity of amorphous materials in two dimensions is introduced, and studied through numerical simulations in order to elucidate the macroscopic (large scale) mechanical behavior. Plastic deformation is assumed to occur through a series of local reorganizations. Using a discretization of the mechanical fields on a discrete lattice, local reorganizations are modeled as local slip events. Local yield stresses are randomly distributed in space and invariant in time. Each plastic slip event induces a long-ranged elastic stress redistribution. Rate and thermal effects are not discussed in the present study. Extremal dynamics allows for recovering many of the complex features of amorphous plasticity observed experimentally and in numerical atomistic simulations in the quasi-static regime. In particular, a quantitative picture of localization, and of the anisotropic strain correlation both in the initial transient regime, and in the steady state are provided. In addition, the preparation of the amorphous sample is shown to have a crucial effect of on the localization behavior.