Molecular Simulation Study on the Influence of the Scratching Velocity on Nanoscopic Contact Processes

The influence of the scratching velocity on mechanical and thermal properties of a nanoscopic contact process was studied by molecular dynamics simulations. Simulations with different scratching velocities were conducted in dry and lubricated systems. The contact process consisted of a lateral scratching of a spherical indenter on a planar substrate. All molecular interactions were described by the Lennard-Jones truncated and shifted potential. The forces on the indenter, the coefficient of friction and the work done by the indenter as well as the power applied on the indenter were sampled. Furthermore, an analysis of thermal properties was conducted: The change of the energy of the substrate, the indenter and the fluid was evaluated and the local temperature field was determined. The forces, the coefficient of friction and the work done by the indenter show practically no influence of the scratching velocity. The work done by the indenter was found to be the same for all velocities. As a consequence, the power supplied to the system depends linearly on the scratching velocity, which affects the temperature of the contact zone. As expected, the presence of a lubricant reduces the temperature of the substrate in the vicinity of the contact