Squeeze Film Damping of Non-Newtonian Fluids

Abstract

In order to determine the overall dynamic response of a machine to a forcing function the damping effect of the bearings in the machine must be known. The damping effect of oil lubricated bearings has been widely published, but the squeeze film damping effect of grease lubricated bearings has hitherto been unestablished. It has been assumed in the past that the grease can be treated as a Newtonian fluid with a viscosity equal to that of the base oil. This assumption is shown to produce damping coefficients which overestimate the actual damping coefficient by up to a factor of 7.