Elastic Bearings Lubricated With Non-Newtonian Power Law Fluids—A Boundary Element Approach

Abstract

This paper discusses the influence of two material property effects on the hydrodynamic lubrication of large-slenderness-ratio, plane slider bearings. Bearing surfaces are covered with an elastic material. This uniformly thick elastic material deforms under the hydrodynamic fluid film pressure. The elastic layer is incompressible (i.e. Poisson ratio is ½). The lubricant is a power-law, non-Newtonian fluid with shear thinning properties. A boundary element method is wed to determine the elastic solid deformation. The important dimensionless parameter coupling the elastic deformation and hydrodynamic pressure is the deformation number. A comparison of bearing pressure profiles and bearing gap-geometries for different fluids is shown. Results reveal increased bearing gaps due to deformation, gap geometries that are more uniform in thickness due to fluid film pressure, pressure peaks moving rearward with increased bearing deformation, sharper converging gaps formed near the bearing trailing edge, and effective hydrodynamic-wedge angles that are decreased by bearing surface deformation.