Hysteresis and competition between disorder and crystallization in sheared and vibrated granular flow

TL;DR

This study investigates how vibration and shear influence phase transitions in granular materials, revealing hysteresis, the coexistence of crystalline and disordered states, and the relationship between kinetic energy and phase behavior.

Contribution

It demonstrates the interplay of vibration and shear in controlling granular phase transitions, highlighting hysteresis and the conditions for crystallization and melting.

Findings

Crystallized state can be melted by shear at sufficient vibration levels.

Force distribution varies between crystalline and disordered states.

Critical transition line aligns with equal kinetic energies of vibration and shear.

Abstract

Experiments on spherical particles in a 3D Couette cell vibrated from below and sheared from above show a hysteretic freezing/melting transition. Under sufficient vibration a crystallized state is observed, which can be melted by sufficient shear. The critical line for this transition coincides with equal kinetic energies for vibration and shear. The force distribution is double-peaked in the crystalline state and single-peaked with an approximately exponential tail in the disordered state. A linear relation between pressure and volume ($dP/dV > 0$) exists for a continuum of partially and/or intermittently melted states over a range of parameters.