On the study of local stress rearrangements during quasistatic plastic shear of a model glass: do local stress components contain enough information?

TL;DR

This study investigates local stress components in a 2D amorphous solid under quasistatic shear, revealing that local stresses alone do not fully capture plastic behavior, which involves additional variables beyond local stress states.

Contribution

It demonstrates that local stress components are insufficient to describe plasticity in amorphous solids, highlighting the need for additional variables beyond local stresses.

Findings

Local stress distributions resemble sums of quadrupolar events.

The position of quadrupole centers is unrelated to local stress evolution.

Local stresses alone do not fully predict plastic rearrangements.

Abstract

We present a numerical study of the mechanical response of a 2D Lennard-Jones amorphous solid under steady quasistatic and athermal shear. We focus here on the evolution of local stress components. While the local stress is usually taken as an order parameter in the description of the rheological behaviour of complex fluids, and for plasticity in glasses, we show here that the knowledge of local stresses is not sufficient for a complete description of the plastic behaviour of our system. The distribution of local stresses can be approximately described as resulting from the sum of localized quadrupolar events with an exponential distribution of amplitudes. However, we show that the position of the center of the quadrupoles is not related to any special evolution of the local stress, but must be described by another variable.