Avalanches and Structural Change in Cyclically Sheared Silica Glass

TL;DR

This study computationally analyzes avalanches and structural changes in silica glass under cyclic shear, revealing unique avalanche statistics, a new relation between exponents, and structural densification linked to strain localization.

Contribution

It introduces a novel relation between avalanche and cluster size distribution exponents and details the structural densification during yielding in silica glass.

Findings

Avalanche statistics in silica glass show non-trivial behavior.

A new relation between avalanche and cluster exponents is verified.

Structural densification and suppression of tetrahedral order occur during yielding.

Abstract

We investigate avalanches associated with plastic rearrangements and the nature of structural change in the prototypical strong glass, silica, computationally. Although qualitative aspects of yielding in silica are similar to other glasses, we find that the statistics of avalanches exhibits non-trivial behaviour. Investigating the statistics of avalanches and clusters in detail, we propose and verify a new relation between exponents characterizing the size distribution of avalanches and clusters. Across the yielding transition, anomalous structural change and densification, associated with a suppression of tetrahedral order, is observed to accompany strain localisation.