Modelling the evolution of flow-induced anisotropy of concentrated suspensions

TL;DR

This paper develops a modified theoretical model to better predict how flow history influences the anisotropic mechanical responses of concentrated suspensions under unsteady flow conditions.

Contribution

It introduces a simple modification to the Gillissen-Wilson model, enhancing its predictive accuracy for steady and unsteady shear flows.

Findings

Modified model shows higher predictive power in steady state.

Model accurately captures anisotropy during shear rotations.

Validation against DEM simulation data confirms improvements.

Abstract

Suspensions, which exhibit complex behaviors such as shear thickening, thinning, and jamming, are prevalent in nature and industry. However, predicting the mechanical properties of concentrated suspensions, in both steady state and the transient regime, remains a significant challenge, impacting product quality and process efficiency. In this study, we focus on developing a robust theoretical framework to explain how flow history governs the anisotropy of mechanical responses in suspensions of hard particles under unsteady flow conditions. Our starting point is the Gillissen-Wilson constitutive model, which we confront to DEM simulation data of the micro-structure during steady shear, and shear rotations where the shear axis is rotated by a specific angle around the flow gradient direction. We introduce a simple modification to the Gillissen-Wilson model which leads to a model with higher predictive power in steady state and during shear rotations.