Nanoscale origins of dynamic friction in an asymmetric contact geometry

Friction, adhesion, and bounce dynamics are found to be asymmetric with respect to sliding direction for a tilted pad sliding at high speed. The differences originate from the nanoscale effects of the mechanical action against the lubricant layer forming an asymmetric meniscus around the pad and from a self-excited vibration induced by friction hysteresis coupled with adhesion hysteresis.