Plastic response and correlations in athermally sheared amorphous solids

TL;DR

This study uses molecular dynamics simulations to explore how localized shear transformations in amorphous solids induce plastic responses and correlations, revealing the influence of prior shear strain and shear rate on these phenomena.

Contribution

It provides new insights into the plastic response and correlations in amorphous solids under shear, highlighting the role of pre-shear and shear rate effects.

Findings

Plastic response is negligible in as-quenched configurations.

Shear response exhibits four-fold symmetry related to stress redistribution.

A fluctuation-dissipation relation is observed at high shear rates, breaking down at lower rates.

Abstract

The onset of irreversible deformation in low-temperature amorphous solids is due to the accumulation of elementary events, consisting of spacially and temporally localized atomic rearrangements involving only a few tens of atoms. Recently, numerical and experimental work addressed the issue of spatio-temporal correlations between these plastic events. Here, we provide further insight into these correlations by investigating, via molecular dynamics (MD) simulations, the plastic response of a two-dimensional amorphous solid to artificially triggered local shear transformations. We show that while the plastic response is virtually absent in as-quenched configurations, it becomes apparent if a shear strain was previously imposed on the system. Plastic response has a four-fold symmetry which is characteristic of the shear stress redistribution following the local transformation. At high shear rate we report evidence for a fluctuation-dissipation relation, connecting plastic response and correlation, which seems to break down if lower shear rates are considered.