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

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 two-dimensional 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 angle-averaged displacement field associated with the plastic drops and the shear localization.