‘Flow and jam’ of frictional athermal systems under shear stress

Abstract

We report recent results of molecular dynamics simulations of frictional athermal particles at constant volume fraction and constant applied shear stress, focussing on a range of control parameters where the system first flows, but then jams after a time t _jam. On decreasing the volume fraction, the mean jamming time diverges, while its sample fluctuations become so large that the jamming time probability distribution becomes a power law. We obtain an insight into the origin of this phenomenology focussing on the flowing regime, which is characterised by the presence of a clear correlation between the shear velocity and the mean number of contacts per particle Z, whereby small velocities occur when Z acquires higher values.

Keywords:

• jamming
• kinetic arrest
• granular materials
• rheology
• phase diagrams

Acknowledgements

We acknowledge computer resources from the University of Naples Scope grid project, CINECA, CASPUR and DEISA.