Discontinuous shear thickening of dense suspensions under confining pressure

Abstract

We use 2D numerical simulations to study dense suspensions of non-Brownian hard particles using the Critical Load Model (CLM) under constant confining pressures. This simple model shows discontinuous shear thickening (DST) as the tangential forces get activated upon increased shear stresses. By parameterizing a simple binary system of frictional and non-frictional particles of different proportions we show that the jamming packing fraction, at which the viscosity diverges, is controlled by the fraction of frictional contacts. The viscosity of dense suspensions can thereby be expressed as a function of the fraction of frictional contacts as well as the packing fraction of solid particles. In addition, we show that there exists a simple relationship between the fraction of frictional contacts and the two control parameters (under confining pressure): the viscous number J and the ratio between the repulsive barrier force and confining pressure. Under confining pressures the viscosity curves are found to depend on the shear protocol, with the possibility of yielding negative dynamic compressibility.

8 pages, 9 figures

References in corpus (3)

• Macroscopic Discontinuous Shear Thickening vs Local Shear Jamming in Cornstarch
• Non-monotonic flow curves of shear thickening suspensions
• Effect of Friction on Dense Suspension Flows of Hard Particles

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• Flow and Arrest in Stressed Granular Materials
• Extended $\mu (J)$-rheology for dense suspensions at oscillatory shear flows
• Shear thickening of suspensions of dimeric particles