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Influence of the elastic deformations on the journal bearing stability in non-newtonian medium
by
Juliana G. Javorova
University of Chemical technology and Metallurgy
Coauthors: Vassil A. Alexandrov, Kiril G. Stanulov
The dynamic behaviour of the system journal-lubricant film in a hydrodynamic (HD) journal bearing with finite length is studied. Focusing particular attention on the influence of the elastic deformations of the shaft liner on the bearing stability, the effect of the rheological properties of the lubricant through its effective viscosity is taken into consideration as well. In this way a complex solution of the problem is achieved. It is assumed that the shaft center motion is a small oscillation around the stable position.
The rheological model, proposed by Eyring is adopted here to describe the non-Newtonian properties of the lubricant. A generalized Reynolds-Eyring equation for determination of the effective viscosity of the lubricant is used.
There are the considerable solutions, using linear approximate methods to calculate the elastic deformations of the contact surfaces points (Higginson, Kodnir, etc.). In the present study a more precise, nonlinear method is proposed, solving a plane mixed problem of the theory of elasticity, where the stress functions, defined by Neuber and the Fourier integral transforms are used.
The energy equation is written with the assumption that the temperature variation across the film is neglected (adiabatic solution). The influence of the temperature on the viscosity is determined according to Roelands.
In the present study modified stability criteria by Hurwitz and Ljapunov are used. They are determined through the functional relation between load parameter (Sommerfeld number), angular velocity of the shaft and the fixed position of the shaft center on the trajectory of its movable equilibrium.
Date received: March 1, 2004
Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cakt-88.