Constitutive model for time-dependent flows of shear-thickening suspensions

TL;DR

This paper introduces a tensorial constitutive model for dense shear-thickening suspensions under time-dependent flow, integrating microstructure evolution and frictional contact proliferation, validated against particle-level simulations.

Contribution

It presents a novel tensorial model combining microstructure evolution with shear-thickening mechanisms, applicable to time-dependent flows.

Findings

Good qualitative agreement with discrete-element simulations.

Model captures shear reversal behavior.

Highlights role of frictional contacts in shear-thickening.

Abstract

We develop a tensorial constitutive model for dense, shear-thickening particle suspensions subjected to time-dependent flow. Our model combines a recently proposed evolution equation for the suspension microstructure in rate-independent materials with ideas developed previously to explain the steady flow of shear-thickening ones, whereby friction proliferates among compressive contacts at large particle stresses. We apply our model to shear reversal, and find good qualitative agreement with particle-level, discrete-element simulations whose results we also present.