Evaluation of the "disorder temperature" and "free volume" formalisms via simulations of shear banding in amorphous solids

TL;DR

This study uses molecular dynamics simulations to test the validity of the disorder temperature and free volume models in describing shear banding in amorphous solids, revealing scaling behaviors related to structural state variables.

Contribution

It provides a quantitative analysis linking local potential energy to disorder temperature and free volume models in shear banding phenomena.

Findings

Scaling of plastic strain rate with disorder variables observed

Potential energy at zero disorder temperature estimated

Energy required for shear transformation zones approximated

Abstract

Molecular dynamics simulations of shear band development over 1000% strain in simple shear are used to test whether the local plastic strain rate is proportional to exp(-1/chi), where chi is a dimensionless quantity related to the "disorder temperature" or "free volume" that characterizes the structural state of the glass. Scaling is observed under the assumption that chi is linearly related to the local potential energy per atom. This analysis permits the extraction of the potential energy per atom at which chi=0 and the approximate energy needed to create a shear transformation zone.