FLUID FILM LUBRICATION WITH NONLINEAR FOUR-ELEMENT VISCOELASTIC FLUIDS (FLOW CHARACTERISTICS, A MODIFIED REYNOLDS EQUATION AND ITS APPLICATION TO PARALLEL CIRCULAR SQUEEZE BEARINGS).

The objective of this study is to establish an analytical procedure for viscoelastic fluid film lubrication based on a nonlinear four-element model, which should apply to lubricating oils containing a large quantity of high molecular-weight polymers. It is made clear from the flow characteristic test that the viscoelastic behavior of such lubricants is represented by a rheology equation based on a four-element model which consists of two nonlinear dashpots and two nonlinear springs. A modified Reynolds equation for finite-width bearings is derived by employing the nonlinear rheology equation. The effects of nonlinear viscoelastic characteristics on the film pressure are then studied with a parallel circular squeeze bearing, and it is shown that the experimental results agree well with the theoretical predictions.