Shear thickening and jamming of bidisperse dense suspensions*

The mechanism of shear thickening in dense suspensions has been linked to a stress-controlled transition from a lubricated "frictionless'' to an unlubricated "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 1:12) and volume fraction of small particles. We find that at a constant volume fraction, the critical shear stress and frictional viscosity can be tuned through the size ratio and volume fraction of small particles. In this presentation, we will investigate these bidisperse systems' network characteristics and microstructure to disentangle the contribution of various types of contacts on the simulated rheology suspensions.