Finite width of quasi-static shear bands

TL;DR

This paper investigates the width and shape of shear bands in amorphous materials under shear, revealing scaling laws and geometric profiles through stochastic modeling and simulations.

Contribution

It introduces a mesoscopic stochastic model to analyze shear band width scaling and shape in both 2D and 3D geometries, connecting to directed polymer models.

Findings

Surface width scales as H^0.68 in 2D

Surface width scales as H^0.60 in 3D

Shear band shape approximates a quarter circle in 3D

Abstract

I study the average deformation rate of an amorphous material submitted to an external uniform shear strain rate, in the geometry known as the split-bottom configuration. The material is described using a stochastic model of plasticity at a mesoscopic scale. A shear band is observed to start at the split point at the bottom, and widen progressively towards the surface. In a two-dimensional geometry the average statistical properties of the shear band look similar to those of the directed polymer model. In particular, the surface width of the shear band is found to scale with the system height H as H^q with q=0.68 +/- 0.02. In more realistic three dimensional simulations the exponent changes to q=0.60 +/- 0.02 and the bulk profile of the width of the shear band is closer to a quarter of circle, as it was observed to be the case in recent simulations of granular materials.