Thermal Activation of Dry Sliding Friction at The Nano-scale

Abstract

Molecular dynamic (MD) simulations are applied to investigate the dependency of the kinetic friction coefficient on the temperature at the nano-scale. The system is comprised of an aluminum spherical particle consisting of 32000 atoms in an FCC lattice sliding on a stack of several layers of graphene, and the simulations have done using LAMMPS. The interaction potential is charge-optimized many-body (COMB3) potential and a Langevin thermostat keep the system at a nearly constant temperature. With an assumption of linear viscous friction, $F_{fr}=-\gamma v$, the kinetic friction coefficient $\gamma$ is derived and plotted at different temperatures in the interval of $T\in [1,600]K$. As a result, by increasing temperature, the kinetic friction coefficient is decreased. Consequently, while the friction is assumed as a linear viscous model, the results are similar to the thermal activation in atomic-scale friction. That is, (1) by increasing sliding velocity friction force will be increased and (2) by increasing temperature, kinetic friction coefficient decreases.

7 pages, 5 figures

References in corpus (2)

• Dynamics of Graphene/Al Interfaces using COMB3 Potentials
• Thermal effects and spontaneous frictional relaxation in atomically thin layered materials