Non-linearities in misaligned journal bearings

Abstract An analysis of hydrodynamic Newtonian lubrication for misaligned journal bearings is given. The primary aim of this paper is to model the non-linearities that occur in a hydrodynamic journal bearing in both aligned and misaligned conditions, and to present the non-linear stiffness, damping and hybrid coefficients in the form of diagrams that can be used in a dynamic analysis of journal bearings. The Reynolds equation is solved using the finite element solution technique. A two-dimensional Newton-Raphson method is used to locate the journal equilibrium position from which both linear and non-linear bearing dynamic coefficients are evaluated by means of the small perturbation technique. The bearing dynamic coefficients, linear and non-linear, due to displacements and to rotations for partial arc, and full journal bearings are calculated for various L / D ratios and misalignment conditions. The effects of misalignment on the linear and non-linear plain journal bearing characteristics are analysed and presented.