A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing

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...

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Main Authors: Jerzy T. Sawicki, T. V. V. L. N. Rao
Format: Article
Language:English
Published: Wiley 2004-01-01
Series:International Journal of Rotating Machinery
Online Access:http://dx.doi.org/10.1155/S1023621X04000508
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author Jerzy T. Sawicki
T. V. V. L. N. Rao
author_facet Jerzy T. Sawicki
T. V. V. L. N. Rao
author_sort Jerzy T. Sawicki
collection DOAJ
description 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.
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spelling doaj-art-e149f4e2809348f2b246dde7dd16f0ec2025-08-20T03:21:05ZengWileyInternational Journal of Rotating Machinery1023-621X2004-01-0110650751310.1155/S1023621X04000508A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal BearingJerzy T. Sawicki0T. V. V. L. N. Rao1Rotor–Bearing Dynamics & Diagnostics Laboratory, Department of Mechanical Engineering, Cleveland State University, 2121 Euclid Ave., SH 245, Cleveland 44115-2214, OH, USABirla Institute of Technology and Science, Pilani, IndiaThis 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.http://dx.doi.org/10.1155/S1023621X04000508
spellingShingle Jerzy T. Sawicki
T. V. V. L. N. Rao
A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
International Journal of Rotating Machinery
title A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
title_full A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
title_fullStr A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
title_full_unstemmed A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
title_short A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing
title_sort nonlinear model for prediction of dynamic coefficients in a hydrodynamic journal bearing
url http://dx.doi.org/10.1155/S1023621X04000508
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