Thin films in elastohydrodynamic lubrication: the contribution of experiment

This paper reviews the various experimental techniques that have contribute d to an understanding of elastohydrodynamic (EHD) lubrication. After a brie f historical overview, attention focuses on the main methods for studying t he behaviour of lubricant films in lubro, within EHD contacts, in particula r ultra thin film interferometry, film thickness mapping, in-contact infrar ed and Raman spectroscopy, fluorescence and temperature/shear stress mappin g. From this review, the important role of the experimentalist in the study of EHD lubrication is identified and appreciated.