Elastohydrodynamics in counterformal and conformal contacts

Since Peppler [1] in 1936 showed that elastic deformation of the mating surfaces in lubricated concentrated contacts plays a dominant role in the pressure built up and film formation, elastohydrodynamic lubrication (E.H.L.) has become a major field of interest in Tribology (Lubrication, Friction and Wear), all over the world. This, of course, is no surprise, since many contacts in machine elements are counterformal and the life of the machine concerned is mainly determined by the life of its most critical parts i.e. the mating surfaces. Examples are rolling element bearings, gears, seals, cam and tappets, etc. The most widely known example of a conformal contact is a journal bearing. In this paper a review will be given with regard to models and calculational methods concerning film thickness, pressure distribution and traction in E.H.L. and research results, recently obtained at the University of Twente, will be presented. Advantages of application of multilevel techniques will be demonstrated. Additionally some experimental results will be shown and some applications will be discussed.