Orientation of plastic rearrangements in two-dimensional model glasses under shear

TL;DR

This study introduces three computational methods to analyze the size and orientation of shear transformations in 2D amorphous solids under shear, revealing broad orientation distributions unaffected by shear rate.

Contribution

The paper presents novel computational techniques for characterizing shear transformations in 2D glasses, enhancing understanding of their size and orientation distributions.

Findings

Shear angles are broadly distributed around the macroscopic shear direction.

Size and orientation distributions are insensitive to shear rate.

Shear angles follow a Gaussian distribution with ~20° standard deviation.

Abstract

The plastic deformation of amorphous solids is mediated by localized shear transformations involving small groups of particles rearranging irreversibly in an elastic background. We introduce and compare three different computational methods to extract the size and orientation of these shear transformations in simulations of a two-dimensional (2D) athermal model glass under simple shear. We find that the shear angles are broadly distributed around the macroscopic shear direction, with a more or less Gaussian distribution with a standard deviation of around 20 $\bullet$ about the direction of maximal local shear. The distributions of sizes and orientations of shear transformations display no substantial sensitivity to the shear rate. These results can notably be used to refine the description of rearrangements in elastoplastic models.