Friction laws for elastic nanoscale contacts
Institut für Physik, Johannes Gutenberg-Universität -
55099 Mainz, Germany
Accepted: 16 March 2001
The effect of surface curvature on the law relating frictional forces F with normal load L is investigated by molecular dynamics simulations as a function of surface symmetry, adhesion, and contamination. Curved, non-adhering, dry, commensurate surfaces show a linear dependence, , similar to dry flat commensurate or amorphous surfaces and macroscopic surfaces. In contrast, curved, non-adhering, dry, amorphous surfaces show similar to friction force microscopes. Curved lubricated or contaminated surfaces show again different behaviour; details depend on how much of the contaminant gets squeezed out of the contact. The shear stress distribution in the contact is highly non-uniform in all cases, i.e. it is seen that the friction force in the lubricated case is mainly due to atoms at the entrance of the tip.
PACS: 81.40.Pq – Friction, lubrication, and wear / 46.55.+d – Tribology and mechanical contacts / 07.79.Sp – Friction force microscopes
© EDP Sciences, 2001