Chaos and bifurcation of a flexible rotor supported by porous squeeze couple stress fluid film journal bearings with non-linear suspension

2008 ◽  
Vol 35 (2) ◽  
pp. 358-375 ◽  
Author(s):  
Cai-Wan Chang-Jian ◽  
Chao-Kuang Chen
Keyword(s):  
Couple Stress ◽  
Journal Bearings ◽  
Fluid Film ◽  
Couple Stress Fluid ◽  
Flexible Rotor ◽  
Non Linear

Non-linear dynamic analysis of bearing—rotor system lubricating with couple stress fluid

2008 ◽  
Vol 222 (4) ◽  
pp. 599-616 ◽  
Author(s):  
C-W Chang-Jian ◽  
C-K Chen
Keyword(s):  
Dynamic Analysis ◽  
Chaotic Motion ◽  
Couple Stress ◽  
Couple Stress Fluid ◽  
Speed Ratio ◽  
Non Linear ◽  
System Life ◽  
The Stability ◽  
Suitable System ◽  
Bearing System

The current study performs a dynamic analysis of a rotor supported by two couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor centre and bearing centre are studied. The analysis of the rotor—bearing system is investigated under the assumptions of a couple-stress lubricant and a short journal bearing approximation. The displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The analysis methods employed in this study include the dynamic trajectories of the rotor centre and the bearing centre, Poincaré maps, and bifurcation diagrams. The Lyapunov exponent analysis is also used to identify the onset of chaotic motion. Numerical results show that the stability of the system varies with the non-dimensional speed ratios. Specifically, it is found that the system is quasi-periodic at a small speed ratio ( s = 0.5). At speed ratios of s = 0.6–0.7, the system is periodic. At s = 0.8–1.9, the system is quasi-periodic, but the system is periodic at s = 2.0–2.6. However, the system exhibits chaotic motion at the speed ratios s = 2.7–2.74. At the speed ratios s = 2.75–3.16, the system becomes periodic. At s = 3.17–3.30, the system is unstable. The Poincaré map has a particular form at s = 3.17, indicative of a chaotic motion. At s = 3.31–6.0, the system finally becomes periodic. The results also confirm that the stability of the system varies with the non-dimensional speed ratios s and l∗. The results of this study allow suitable system parameters to be defined such that undesirable behaviour of the rotor centre can be avoided and the bearing system life extended as a result.

scholarly journals Inertia Effects in a Multilobe Conical Bearing Lubricated with a Couple Stress Fluid

2019 ◽  
Vol 24 (2) ◽  
pp. 439-451
Author(s):  
A. Walicka ◽  
E. Walicki ◽  
P. Jurczak
Keyword(s):  
Galerkin Method ◽  
Couple Stress ◽  
Fluid Flows ◽  
Journal Bearings ◽  
Couple Stress Fluid ◽  
Mechanical Parameters ◽  
Inertia Effects ◽  
Bearing Clearance ◽  
Conical Bearing ◽  
The Galerkin Method

Abstract In this paper, a multilobe conical bearing is analyzed. A lubricant modelled by a couple stress fluid flows in the bearing clearance. The Galerkin method is used to determine the mechanical parameters of multilobe journal bearings. An example of a two-lobe conical bearing is discussed in detail. The inertia of the flowing lubricant is taken into account in the analysis. It has been found that the increase of the couple stress generates an increase the pressure in the clearance.

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