A Traction (Friction) Curve Is Not a Flow Curve

With the uncertainty regarding global energy future, ability to lubricate concentrated contacts with sufficiently thick liquid films while minimizing friction is of extreme importance. The assumptions classical elastohydrodynamic lubrication have remained unchanged since early days. It has not been possible test many these without measurement viscosity at (EHL) pressures, and viscometer measurements ignored. One equivalence a traction curve rheological flow for lubricant. This notion should discarded forty years ago, simply because it required pressure–viscosity behavior be unlike observed in viscometers. At heart problem fact that pressure within EHL contact homogeneous properties are highly dependent on pressure, making very poor rheology laboratory. These past failures must avoided future.