The pressure-viscosity coefficient for Newtonian EHL film thickness with general piezoviscous response

There has been a long-standing need for a piezoviscous parameter [[alpha].sub.film] that, together with the ambient viscosity [[micro].sub.0], will completely quantify the Newtonian rheology so that the film thickness for liquids that do not shear-thin in the inlet may be calculated as h = h([[micro].sub.0], [[alpha].sub.film], ...), regardless of the details of the pressure-viscosity response. It seems that Blok's reciprocal asymptotic isoviscous pressure has certain advantages over the conventional pressure-viscosity coefficient, which is poorly suited for this purpose. The first detailed review of piezoviscous models for low pressures is provided. A simulation code that is apparently stable for all realistic pressure-viscosity response was utilized with diverse piezoviscous models and model liquids to develop a satisfactory definition of [[alpha].sub.film] that reads [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]; 1/[[alpha].sup.*] = [[integral].sup.[infinity].sub.0] [micro](0)dp/[micro](p). In the case of [micro] = [[micro].sub.0] exp ([[alpha]p]), [[alpha].sub.film] = [alpha] and formulas are provided for other models. [DOI: 10.1115/1.2197846] Keywords: pressure-viscosity coefficient, Newtonian, piezoviscous, film thickness, elastohydrodynamics