Analytic theory of shear localization in amorphous solids confined by Couette geometry

TL;DR

This paper develops an analytic theory to predict shear localization phenomena in a 2D amorphous solid under Couette shear, explaining displacement fields and plastic avalanches.

Contribution

It introduces a novel analytic framework for understanding shear localization in amorphous solids under Couette geometry, predicting displacement fields and plastic events.

Findings

Analytic predictions match observed shear localization patterns.

Displacement fields associated with plastic drops are quantitatively described.

The theory explains the formation of shear bands and opposite rotations.

Abstract

``Couette geometry'' refers to two concentric rings in 2-dimensions (or cylinders in 3-dimensions with a medium in between. Typically the inner and outer rings (or cylinders) rotate at different rates and the response of the medium is studied. Here we study a medium which is a twodimensional amorphous solid, and we rotate the inner ring quasi-statically. As stress accumulates, plastic avalanches can result in shear localization, characterized by adjacent parts of the system rotating in opposite directions, with the maximum shear localized between them. We derive an analytic theory that describes and explains the shear localization, providing a-priori predictions for the displacement field associated with the plastic drops and the shear localization.