ABSTRACT
Friction and wear between contacting surfaces in relative motion is determined by both the intrinsic properties of the materials and by external factors linked to the end users’ field conditions. Contacting surfaces between two solid bodies are of interest to two complementary disciplines, namely mechanics and tribology. However, the mechanical approach differs from the tribological one. Indeed, tribologists link measurable macroscopic parameters (such as the coefficient of friction) to geometrical and mechanical characteristics of surfaces (such as roughness, debris) while considering the bulk of the materials as an elastic characteristic. On the other hand, mechanical engineers consider the surface of materials as a transfer zone of load (for example, described as Hertz contact pressure) allowing them to calculate precisely material changes in the vicinity of their surface (elastoplastic behaviour, strain hardening), and the eventual material failure under the prevailing loading conditions (like multi-axial fatigue criteria). In this section, the important factors that influence friction and wear are critically reviewed for both unlubricated and lubricated contacts. Commonly used data analysis methods for the interpretation of friction and wear data obtained from laboratory testing or simulation are presented.
