Abstract
The deformation of sliding objects plays an important role for determining the characteristics of frictional vibration. Therefore, to understand the frictional vibration of elastomers comprehensively, in-situ observations of contact area are necessary along with force measurements. In this article, after explaining the basics of frictional vibration using a single-degree-of-freedom model, some optical methods of visualizing the contact area (i.e., methods using transmission or reflection of visible light) are introduced. In particular, methods using the total reflection are hopeful to realize sensitive observations of contact area under dry or wet conditions.
