Analysis of dynamic characteristics of hydrodynamic journal bearings with isotropic roughness effects

Stability analysis of rough journal bearings under TEHL with non-Newtonian lubricants

S iv ACKNOWLWDGEMENTS vi TABLE OF CONTENTS viii LIST OF TABLES xii LIST OF FIGURES xvii NOMENCLATURE xx CHAPTER 1: INTRODUCTION 1 1.1. General Background 1 1.2. Lubrication of the Components of Aeronautical Power Systems 4 1.3 The Scope of the Present Work 6 CHAPTER 2: CURRENT RESEARCH IN SQUEEZE FILM DAMPERS 8 2.

Numerical predictions and measurements in the lubrication of aeronautical engine and transmission components

Influence of surface roughness effects on the performance of non-recessed hybrid journal bearings

On the basis of Stokes theory and the Christensen's stochastic model, the combined effects of couple stresses and surface roughness on the instability threshold of hydrodynamic rotor bearings are theoretically studied. The film pressure is solved from the generalized stochastic non-Newtonian Reynolds-type equation and applied to evaluate the equilibrium solution of a short journal bearing. By using the linear theory, the eight oil-film stiffness and damping coefficients as well as the vibrational stability boundary were determined. According to the results obtained, the presence of couple stresses accompanied with a longitudinal roughness provides an increase in the values of stiffness coefficientsKXX, KXY and KYX as well as the damping coefficient CXX, and results in a higher stability threshold speed. Whereas, when compared to the smooth bearing lubricated with couple stress fluid, a decrease in the threshold speed is found in the case of transverse roughness.

Linear Stability Analysis of a Rough Short Journal Bearing Lubricated with Non-Newtonian Fluids

This investigation deals with the stability of rigid rotors supported on finite rough oil journal bearings using perturbation method. The effect of various surface roughness parameters, viz., composite surface roughness, roughness orientation pattern and variance ratio on the stability has been studied. In general, surface roughness effect when incorporated into the analysis does not show a significant change in the stability for surfaces having same roughness structure. However, the effect of variance ratio (i.e., surfaces having different roughness structure) on stability is quite marked

M. K. Ghosh

Papers

Stability of a Rigid Rotor Supported on Rough Oil Journal Bearings