Self-organization and memory in a cyclically driven elasto-plastic model of an amorphous solid

TL;DR

This paper investigates how a mesoscopic elasto-plastic model of amorphous solids exhibits memory effects, including directional memory and irreversibility transitions, using a Preisach-like framework to describe these phenomena.

Contribution

It introduces a quenched mesoscopic elasto-plastic model demonstrating memory effects and develops a simple Preisach-like model to explain directional memory in amorphous solids.

Findings

Memory of shear direction emerges from mechanical polarization.

Sample-to-sample fluctuations reveal irreversibility transition.

Behavior close to Return Point Memory observed despite elastic interactions.

Abstract

The mechanical behavior of disordered materials such as dense suspensions, glasses or granular materials depends on their thermal and mechanical past. Here we report the memory behavior of a quenched mesoscopic elasto-plastic (QMEP) model. After prior oscillatory training, a simple read-out protocol gives access to both the training protocol's amplitude and the last shear direction. The memory of direction emerges from the development of a mechanical polarization during training. The analysis of sample-to-sample fluctuations gives direct access to the irreversibility transition. Despite the quadrupolar nature of the elastic interactions in amorphous solids, a behavior close to Return Point Memory (RPM) is observed. The quasi RPM property is used to build a simple Preisach-like model of directional memory.