LAUSR

Abstract In the study of elastohydrodynamic lubrication the rheological properties of the liquid film are essential to understanding and predicting the friction and the film thickness in lubricated concentrated. There are two entirely different approaches to obtain these properties. In the quantitative approach, viscometers and rheometers are used at high pressure. In the classical approach, the same averaged properties are extracted from the contact itself. For more than 40 years the two methods have provided quite different pictures of high-pressure rheology. The claim has been made that the averaging technique provides viscosities that match those from this author's rheometer and viscometer. This claim can easily be shown to be false and the use of the contact as a viscometer must end.