The role of friction in dense, sheared rod-like suspensions: a simulation study

The complex interplay between nematic order, frictional contacts, and flow in dense suspensions of rigid rods has yet to be fully elucidated. Here, we present simulations of suspensions of non-Brownian hard sphere chains under shear, with Coulomb contact friction and lubrication between particles. We measure rod-to-rod contacts at varying nematic order, volume fraction, and aspect ratio; and propose a modified form of Philipse's random contact equation. We discuss the distribution of tangential frictional forces, particularly in the regimes of discontinuous and continuous shear thickening. We also make connection to the Wyart & Cates model for spheres by modelling the viscosity as a function of a jamming fraction and nematic order.