Transient Elastohydrodynamic Lubrication Film Thickness During Normal Approach Considering Shear Thinning and Linear Piezoviscous Oils

Abstract

Transient film thickness behavior is investigated using full elastohydrodynamic lubrication (EHL) line contact simulations during film collapse due to sudden halt and impact loading. Due attention is given to realistic shearthinning behavior and comparisons are made with a largely ignored class of EHL lubricants that exhibit linear pressure–viscosity dependence at low pressures. The EHL film collapse is found to be governed by the piezoviscous response and the linear P–V oils exhibit rapidly collapsing EHL entrapment. Under impact loading, the transient film thickness deviates markedly from the corresponding steadystate behavior and this departure is a function of lubricant rheology.