Jamming phase diagram for frictional particles

TL;DR

This paper extends the jamming phase diagram to include frictional effects in athermal systems, revealing new dynamical regimes where systems can flow or slip before eventually jamming.

Contribution

It introduces a comprehensive jamming phase diagram for frictional particles, accounting for density, shear stress, and friction, highlighting new dynamical regimes not seen in frictionless systems.

Findings

Friction introduces a new region in the phase diagram with unique flow and slip behaviors.

Systems can flow or slip under stress before eventually jamming due to friction.

A phase diagram incorporating frictional effects explains complex dynamical regimes.

Abstract

The non-equilibrium transition from a fluid-like state to a disordered solid-like state, known as the jamming transition, occurs in a wide variety of physical systems, such as colloidal suspensions and molecular fluids, when the temperature is lowered or the density increased. Shear stress, as temperature, favors the fluid-like state, and must be also considered to define the system 'jamming phase diagram' [1-4]. Frictionless athermal systems [1], for instance, can be described by the zero temperature plane of the jamming diagram in the temperature, density, stress space. Here we consider the jamming of athermal frictional systems [8-13] such as granular materials, which are important to a number of applications from geophysics to industry. At constant volume and applied shear stress[1, 2], we show that while in absence of friction a system is either fluid-like or jammed, in the presence of friction a new region in the density shear-stress plane appears, where new dynamical regimes are found. In this region a system may slip, or even flow with a steady velocity for a long time in response to an applied stress, but then eventually jams. Jamming in non-thermal frictional systems is described here by a phase diagram in the density, shear-stress and friction space.