Velocity, temperature and normal force dependence on friction: An analytical and molecular dynamic study

TL;DR

This study extends an analytical friction model to include normal force and directional dependence, validated by molecular dynamics simulations and experimental data, enhancing understanding of frictional behavior under various conditions.

Contribution

The paper introduces an extended analytical friction model incorporating normal forces and directional dependence, validated through molecular dynamics simulations and experimental comparisons.

Findings

Analytical results closely match molecular dynamics simulations.

The model accurately predicts friction behavior under different velocities, temperatures, and normal forces.

Good agreement with experimental results from previous studies.

Abstract

In this work we propose an extension to the analytical one-dimensional model proposed by E. Gnecco (Phys. Rev. Lett. 84:1172) to describe friction. Our model includes normal forces and the dependence with the angular direction of movement in which the object is dragged over a surface. The presence of the normal force in the model allow us to define judiciously the friction coefficient, instead of introducing it as an {\sl a posteriori} concept. We compare the analytical results with molecular dynamics simulations. The simulated model corresponds to a tip sliding over a surface. The tip is simulated as a single particle interacting with a surface through a Lennard-Jones $(6-12)$ potential. The surface is considered as consisting of a regular BCC(001) arrangement of particles interacting with each other through a Lennard-Jones $(6-12)$ potential. We investigate the system under several conditions of velocity, temperature and normal forces. Our analytical results are in very good agreement with those obtained by the simulations and with experimental results from E. Riedo (Phys. Rev. Lett. 91:084502) and Eui-Sung Yoon (Wear 259:1424-1431) as well.