Shear-Thinning at Pressures Above Ambient
The rapid advances in EHL over the last seven years were the result of the incorporation of real viscosity into analyses of film thickness and friction. No small part of this revolution has been the accurate description of shear dependent viscosity, also called shear thinning. Shear thinning is also an issue for hydrodynamic lubrication and there is no reason that the same data and models cannot be applied to plain bearings operating at lower pressures. In fact, shear dependence measurements made at slightly elevated pressure remove most of the extraneous effects, such as shear cavitation and thermal softening, which have hampered interpretation of the measurements made in ambient pressure instruments.