[2Ep01-05] Toward Multiscale Tribology Bridging Nano- and Macro-scale: Science of Friction Division's Session

[2Ep01] The law of friction depends on the scale.

*Hiroshi Matsukawa¹ (1. Department of Physics, Aoyama Gakuin University)

Frictional force between dry solids is directly proportional to the loading force and remains independent of the apparent contact area, a phenomenon termed as Amontons' law. This law's foundation is the adhesion force at real contact areas. Here we discuss law of friction at atomic, mesoscopic and macroscopic scales. At the atomic level, a single contact point's friction depends on atomic arrangements, deviating from Amontons' law. At the mesoscopic scale, collective real contact points produce a frictional force consistent with the law, regardless of individual contact point nature. However, at the macroscopic scale, inherent stress variations can challenge Amontons' law. Thus, friction's behavior varies with the observation scale.