Abstract
A method is presented which allows the simulation of the transient and steady state response of a balanced, flexible shaft supported by a realistic thermohydrodynamic journal bearing system. The analytical model is an accurate presentation of the real shaft-bearing system and includes the following features: (1) large deflections of the shaft up to the proportional limit of the material, (2) gravity and all inertial loadings (including gyroscopic effects) arising from the general three dimensional motion of the shaft, (3) pressure-dependent viscous effects of the incompressible lubricant, (4) wedge and squeeze film effects of the lubricant due to general journal motion (six degrees of freedom), (5) exact computation of the film thickness of the lubricant for any given position and orientation of the journal and, (6) a novel approach to the calculation of the hydrodynamic loads acting on a journal for general journal motion. The bearing model also includes the effects of axial and circumferential lubricant flow as well as the effects of fluid film cavitation. The effect of the introduction of oil via single hole, axial groove, or circumferential groove oil inlets is also considered in the bearing model. The bearings are assumed to be rigidly mounted and perfectly aligned. The elastic shaft is represented as a finite number of straight, rigid shaft elements in the derivation of the equations of motion. The internal loads acting at the ends of each element are computed based on the local deformation of the elastic shaft at those ends. The hydrodynamic loads at the journals (or end-elements) are computed from the known position, orientation, and motion of the journals in the bearings. The coupled nonlinear ordinary differential equations of motion are formulated as an initial-value problem and solutions are obtained by direct integration on a digital computer using the fourth-order Runge-Kutta method. The hydrodynamic loads are obtained for each time increment from a finite-difference solution of the general Reynolds' equation. The technique can be modified to consider the effects of the time-varying temperature field of the lubricant on the hydrodynamic loads; the groundwork for this modification is included in the study...
Stroman, Morris Michael (1979). Dynamic response of a rotating, balanced, flexible shaft supported by a thermohydrodynamic bearing system. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -152770.