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Article
A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
International Journal of Rotating Machinery
  • Jerzy T. Sawicki, Cleveland State University
  • T.V.V.L. N. Rao, Birla Institute of Technology and Science
Document Type
Article
Publication Date
1-1-2004
Abstract

This paper investigates the variation of nonlinear stiffness and damping coefficients in a journal orbit with respect to equilibrium position. The journal orbit is obtained by the combined solution of equations of motion and Reynolds equation. In the linearized dynamic analysis, dynamic pressure is written as a perturbation of static pressure and pressure gradients at equilibrium position. However, in order to obtain nonlinear dynamic coefficients about equilibrium position, the dynamic pressure gradients in the orbit are also written as the first order perturbation of static pressure gradients and higher order pressure gradients for displacement and velocity perturbations. The dynamic coefficients are functions of bearing displacement and velocity perturbations. The higher order pressure gradients at equilibrium position are evaluated at various eccentricity ratios and L/D ratios of 0.5 and 1.0. The variation of nonlinear dynamic coefficients is analyzed for three Sommerfeld numbers of a two-axial groove journal bearing under the action of an external synchronous load along and perpendicular to the radial journal load. Results indicate that the oil film nonlinearities affect the journal motion at lower eccentricity ratios (higher Sommerfeld numbers) with wide variation in stiffness and damping coefficients.

DOI
10.1155/S1023621X04000508
Version
Postprint
Citation Information
Sawicki, J.T. and Rao, T. (2004). A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing. International Journal of Rotating Machinery, 10(6), 507-513, doi: 10.1155/S1023621X04000508.