Introduction 

Many definitions have appeared in publications during the last 15 years of the previous century of what is commonly termed now as tribo-fatigue. Tribo-fatigue has been determined as a “new scientific trend” either in tribology or mechanics of fatigue fracture, or as a “new sphere of activity” in creating reliable mechanical systems, or as a “new branch of mechanics”, and finally as a “science of wear-fatigue damage and fracture of active systems of machines and equipment” [1–5]. It is premature right now either to criticize or support any of these definitions. In our view, it should be stated outright that it is emergence and evolution of the mechanics of wear-fatigue damage [6–8]. This emergence and evolution occur at the borders between three disciplines: tribology, mechanics of fatigue fracture and the theory of reliability of mechanical systems. It is to emphasize that they occur at the borders rather than within any single of these disciplines. Hence, each of these disciplines is a source of tribo-fatigue, its particular, definitely powerful foundation.

Since the mechanics of wear-fatigue damage is dealt with, the term tribo-fatigue [3, 6, 9] quite sufficiently but in short reflects its notion: tribos (from Greek) – friction symbolizes modern tribology, including tribological reliability, fatigue (from French) symbolizes modern mechanics of fatigue fracture, including strength reliability. It is apparent that the term tribo-fatigue combines two words (notions), which are completely equal. If we deal with physico-mechanical processes based on shown above notions, it should be stressed on their dialectic interaction and interaffect correlation (friction (and wear) ó fatigue = tribo-fatigue).

Each scientific discipline has its own specific attributes. Exactly these specific attributes allow to discriminate explicitly what is what.