Overlapping plastic events as a mechanism for irreversible dynamics in amorphous solids under oscillatory shear

TL;DR

This paper investigates how overlapping plastic events in amorphous solids under oscillatory shear lead to irreversibility, revealing that increased plastic activity and overlaps cause the transition from reversible to irreversible behavior.

Contribution

It introduces a mechanism where overlaps between particle rearrangements induce irreversibility, supported by simulations and models, advancing understanding of amorphous solid dynamics under shear.

Findings

Overlaps between plastic events increase with shear amplitude.

Higher plastic activity correlates with greater irreversibility.

Simulations confirm the role of overlaps in transition to irreversible response.

Abstract

The origin of the transition from asymptotically reversible to asymptotically irreversible response in amorphous solids subject to oscillatory shear is still unknown. It is known that the plastic events that result from shearing always involve localized particle rearrangements, but it is unclear why some are reversible while others are not. Here we show, using simulations and models, that overlaps between particle rearrangements caused by straining the solid in alternating directions can cause the response to become irreversible when they occur frequently. As the forcing amplitude increases, plastic events become more frequent, the number of such overlaps increases, and the probability of the system returning to previous states diminishes.