Localized and extended dynamical correlation lengths in jammed packings of soft athermal disks under slow shear

TL;DR

This study uses molecular dynamics simulations to analyze stress drop events in jammed soft disk packings under shear, revealing two distinct types of events—localized and extended—that relate to plasticity and elastic behavior.

Contribution

It identifies and characterizes two different types of stress drop events in sheared jammed packings, linking their spatial structures to the system's elastic and plastic regimes.

Findings

Localized events occur during plastic deformation.

Extended events happen in elastic regimes.

Both event types are driven by oscillatory stress motion.

Abstract

Dynamics of jammed packings of soft athermal disks under finite-rate shear are studied by means of molecular dynamics simulations. Particularly, we investigate the spatial structures of stress drop events, which are expected to provide information about plasticity. Investigating the displacement fields during stress drop events, we show that there are qualitatively different two types of events in the low rate limit: localized ones and extended ones. We further investigate the time evolution of events and clarify that both types of events are due to oscillatory motion of the stress, which is unique for systems under finite-rate shear. The difference between two types of events is the regime that events reside in: while localized events take place during plastic events, extended ones occur in the elastic branch.