The Barus–Roelands–Eyring Viscosity Artifice: A Catastrophe for Elastohydrodynamic Lubrication

Abstract

Abstract. Ward Winer was a pioneer in the high-pressure rheology of liquid lubricants who championed the use of viscometers to understand the rheology of elastohydrodynamic lubrication (EHL). The classical approach to EHL ignores viscosity measured in high-pressure viscometers and substitutes fictional narratives regarding Barus, Roelands, and Eyring to justify the use of viscosities that cannot be measured in viscometers. To make film thickness formulas appear to be accurate, the pressure-viscosity coefficient can be easily adjusted. Lacking an accurate description of the temperature, pressure, and shear dependences of viscosity, researchers have resorted to some unusual assumptions to explain friction. Among these have been time-dependent viscosity, viscoelasticity, and wall-slip. It is well past the appropriate time to begin to base all EHL analysis on empirical fact and end the teaching of the fictional stories concerning rheology to tribology students.