ABSTRACT
This chapter discusses the basic aspects of contact between surfaces in a form accessible to non-contact mechanics specialists. Surfaces are usually rough so contact between them can only occur at a limited number of points. The point of doing so is to develop the basis for discussions on the real area of contact and temperature rise on sliding surfaces. Calculation of stresses and deformation between solids in contact is the subject of contact mechanics, a field of study and specialization in itself for many years. When the two bodies stick together upon loading, a new stress state prevails upon unloading. In the usual case the high stress at the edge of contact is alleviated but not eliminated by plastic flow. Thermal sensitive paints and films is another technique capable of measuring surface temperature in sliding contacts. For opaque materials the measurements may be made after the sliders have separated, with some loss of instantaneous data.
