Collective Behavior of Asperities in Dry Friction at Small Velocities

TL;DR

This paper models dry friction at small velocities using extremal dynamics, revealing self-organized criticality, asperity aging, and a velocity-dependent friction force.

Contribution

It introduces a simple extremal dynamics model for asperities that captures collective behavior and criticality in dry friction at low velocities.

Findings

Correlations between asperities develop at small velocities.

System exhibits self-organized criticality in the slow driving limit.

Friction force depends on velocity as F ~ 1 - exp(-1/v).

Abstract

We investigate a simple model of dry friction based on extremal dynamics of asperities. At small velocities, correlations develop between the asperities, whose range becomes infinite in the limit of infinitely slow driving, where the system is self-organized critical. This collective phenomenon leads to effective aging of the asperities and results in velocity dependence of the friction force in the form $F\sim 1- \exp(-1/v)$.