Science of friction

Friction including wear and lubrication is one of the most familiar physical phenomena and has been investigated from ancient age, but many fundamental problems concerned with the friction are unresolved still now. Recent progress of new experimental equipments and computers enables us to study frictional phenomena of atomic scales. Today frictional phenomena ranging from atomic to geophysical scales are investigated extensively. It turns out that frictional phenomena in various scales show hierarchy and universality.

The one of the main concern of "Science of Friction" is to explain and predict macroscopic frictional phenomena starting from atomic scale studies. The frictional phenomena of the largest scale on the earth are earthquakes, of which largest scale is about 108m. The frictional phenomena of the smallest scale are atomic frictional phenomena, of which typical scale is about 10-6m. Hence the gap between the macroscopic and microscopic frictional phenomena is huge. We must bridge the gap, but it is not easy. Between earthquakes and atomic frictional phenomena there are many degrees with different scales on which every frictional phenomenon occurs. The degrees make hierarchy. We must bridge the every gap between neighboring degrees in the hierarchy and then finally the macroscopic and microscopic frictional phenomena will be connected.

Another interesting aspect of "Science of Friction" is the universality. Many universal phenomena, such as stick-slip motion and precursor slip, appear in frictional phenomena of various scales. But some discrepancies also appear among them. To make clear the features of the phenomena independent of and dependent on the scales from a unified point of view manifests the fundamental mechanism of the frictional phenomena.

In the symposium "Science of Friction", we overview the present status of the hierarchy and universality of friction and discuss the way of bridging the gap between the microscopic and macroscopic frictional phenomena and making clear the features of the frictional phenomena independent of and dependent on the scales. These will lead us to control the friction, lubrication and wear.

Organizers

  • Mark O. Robbins (Johns Hopkins Univ.) / Mark.O.Robbins@jhu.edu
  • Hiroshi Matsukawa (Aoyamagakuin Univ.) / matsu@phys.aoyama.ac.jp