Onset of flow in a confined colloidal glass under an imposed shear stress

TL;DR

This study uses numerical simulations to explore how a confined colloidal glass transitions from a solid-like state to flowing under shear stress, revealing diverging timescales and shear banding near the yield point.

Contribution

It provides new insights into the microscopic and macroscopic dynamics during the onset of flow in confined colloidal glasses under shear stress.

Findings

Onset time for flow diverges near yield stress.

Persistent shear banding observed during creep.

Long-lived spatial heterogeneities linked to flow initiation.

Abstract

A confined colloidal glass, under the imposition of a uniform shear stress, is investigated using numerical simulations. Both at macro- and microscales, the consequent dynamics during the onset of flow is studied. When the imposed stress is gradually decreased, the time scale for the onset of steady flow diverges, associated with long-lived spatial heterogeneities. Near this yield-stress regime, persistent creep in the form of shear-banded structures is observed.