A Small-gap Effective-Temperature Model of Transient Shear Band Formation During Flow

Abstract

Recent Couette-cell shear experiments of carbopol gels have revealed the formation of a transient shear band before reaching the steady state, which is characterized by homogeneous flow. This shear band is observed in the small-gap limit where the shear stress is spatially uniform. An effective-temperature model of the transient shear banding and solid-fluid transition is developed for the small-gap limit. The small-gap model demonstrates the ability of a continuum-constitutive law that is based solely on microstructural rearrangements of the gel to account for this transient behavior, and identifies that it proceeds via two distinct processes. A shear band nucleates and gradually broadens via disordering at the interface of the band. Simultaneously, spatially homogeneous fluidization is induced outside of the shear band where the disorder of the gel grows uniformly. Experimental data are used to determine the physical parameters of the theory, and direct, quantitative comparison is made to measurements of the structural evolution of the gel, its fluidization time, and its mechanical response under plastic flow.

Published in the Journal of Rheology (Special Edition: Shear Banding in Complex Fluids)

References in corpus (13)

• Phenomenology and physical origin of shear-localization and shear-banding in complex fluids
• Strain localization in a shear transformation zone model for amorphous solids
• Evaluation of the "disorder temperature" and "free volume" formalisms via simulations of shear banding in amorphous solids
• On the existence of a simple yield stress fluid behavior
• Shear banding, aging and noise dynamics in soft glassy materials
• Wide-gap Couette flows of dense emulsions: Local concentration measurements, and comparison between macroscopic and local constitutive law measurements through magnetic resonance imaging
• Rate dependent shear bands in a shear transformation zone model of amorphous solids
• Reversible plasticity in amorphous materials
• Transition from a simple yield stress fluid to a thixotropic material
• Steady-state, effective-temperature dynamics in a glassy material
• Investigation of shear banding in three-dimensional foams
• Flow transitions in two-dimensional foams
• Effective Temperature Dynamics in an Athermal Amorphous Plasticity Theory

Cited by in corpus (7)

• Yield Stress Materials in Soft Condensed Matter
• Triggers and signatures of shear banding in steady and time-dependent flows
• Unified theoretical and experimental view on transient shear banding
• Emergence and persistence of flow inhomogeneities in the yielding and fluidization of dense soft solids
• Shear Band Broadening in Simulated Glasses
• Continuum modelling of shear start-up in soft glassy materials
• Start-up inertia as an origin for heterogeneous flow