Tribological variable-friction coefficient models for the simulation of dense suspensions of rough polydisperse particles

The rheology of concentrated suspensions particles is complex and typically exhibits a shear-thickening behavior in the case repulsive interactions. Despite recent interest arisen, causes remain unclear. Frictional contacts have been able to explain discontinuous shear thickening simulations. However, interparticle friction coefficient considered be constant most simulations theoretical works reported date despite fact that tribological experiments demonstrate can not only (boundary regime) but also decrease (mixed or even increase (full-film lubrication regime), depending on normal force relative velocity between interstitial liquid them. Interestingly, transition boundary regime full-lubrication governed by particle average roughness. Particle-level hard spheres were carried out using short-range roughness-dependent frictional forces describing full Stribeck curve. Suspensions with different particle’s roughness simulated show key factor behavior; for sufficiently rough particles, suspension remarkable shear-thickening, while smooth disappears.