Shear jamming in dense bidisperse frictional suspensions

The mechanism of shear thickening in dense suspensions has been linked to a stress-controlled transition from an unconstrained lubricated "frictionless'' to a constrained "frictional'' rheology. Recent particle simulations that constrain the relative motion between particles have been successful to reproduce both the discontinuous shear thickening (DST) and shear jamming (SJ) observed experimentally for rough and smooth particles. However, so far only monodisperse or weakly bidisperse cases are considered. We perform numerical simulations at a fixed volume fraction varying size ratio of particle radii (up to 1:8) and volume fraction of small particles. We find that at a constant volume fraction and size ratio, the viscosity of suspension varies non-monotonically with the fraction of small particles. In this presentation, we will investigate the relative contributions of stress carried by various types of contacts (small-small, small-big, big-big) and their respective microstructure.