Study on non-steady stability of a rotor-journal bearing system (Stability of the 360 degree short bearing).

Rotor bearing systems on ships usually work in inclined states when ships are swaying in wave and wind. The inclined status will affect the lubricant condition of journal bearing and bring about changes of the dynamic characteristics of the rotor system. To study the periodic solution stability of inclined rotor journal bearing system, Capone’s short bearing model is employed to describe the journal bearing support properties. Considering the inclination induced change of bearing radial load, the dynamic equation of inclined rotor system is established by using finite element method. The periodic solution stability is discussed based on bifurcation and response analysis. With the increase of rotating speed, instability of period-1 motion happens and oil whirl occurs. The motion then develops into a kind of quasi-periodic motion. Two special cases of inclined rotor system, the horizontal and the vertical cases, are compared and discussed. Both of the numerical and the experimental results show that the periodic solution unstable threshold decreases with the increase of rotor inclination angle. At last, some experimental results about influences of experiments conditions on rotor system stability are given.

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Dynamic Analysis of a Rotor-Journal Bearing System with Large Dynamic Loads. Stiffness and Damping Coeffcient Variation in Bearing Oil Films.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.57.3606 ◽

1991 ◽

Vol 57 (543) ◽

pp. 3606-3611

Author(s):

Hitoshi HATTORI

Keyword(s):

Dynamic Analysis ◽

Journal Bearing ◽

Dynamic Loads ◽

Rotor Journal ◽

Stiffness And Damping ◽

Oil Films ◽

Bearing System

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Comparison of Effects of Dimensional Manufacturing Tolerances and Journal Out-of-Roundness on Stability of Hydrodynamic Journal Bearing System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.1966 ◽

2011 ◽

Vol 121-126 ◽

pp. 1966-1971

Author(s):

Wu Bin Xu ◽

De Jian Zhou ◽

Peter Ogrodnik ◽

Mike Goodwin

Keyword(s):

Theoretical Analysis ◽

Taguchi Method ◽

Journal Bearing ◽

Journal Bearings ◽

System Stability ◽

Design Stage ◽

Analysis Method ◽

Manufacturing Tolerances ◽

Hydrodynamic Journal Bearing ◽

Bearing System

The manufacturing tolerances of a hydrodynamic journal bearing system are inevitable in manufacturing process. To examine and understand the effect of manufacturing tolerances on the system stability can help engineers to confidently choose reasonable tolerances at design stage. This study presented a theoretical analysis method to determine and compare the effects of dimensional manufacturing tolerances and journal out-of-roundness on system stability by Taguchi method. The results show that the journal out-of-roundness has the most significant effect on the system stability and the journal out-of-roundness appears to stabilize the system. The authors suggest that both dimensional manufacturing tolerances and journal roundness should be taken into account in the design of cylindrical journal bearings.

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Dynamic Analysis of a Rotor-Journal Bearing System with Large Dynamic Loads. Influence of Relative Misalignment between the Bearings on the Characteristics of a Rigid Rotor System.

JSME international journal Ser 3 Vibration control engineering engineering for industry ◽

10.1299/jsmec1988.34.503 ◽

1991 ◽

Vol 34 (4) ◽

pp. 503-511

Author(s):

Hitoshi HATTORI ◽

Noritsugu KAWASHIMA

Keyword(s):

Dynamic Analysis ◽

Journal Bearing ◽

Rotor System ◽

Dynamic Loads ◽

Rigid Rotor ◽

Rotor Journal ◽

Bearing System

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Effect of journal cylindricity error with saddle or drum distribution on the performance of hydrodynamic journal bearing systems

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650119876221 ◽

2019 ◽

Vol 234 (7) ◽

pp. 1092-1105

Author(s):

Bing Li ◽

Dejian Zhou ◽

Peter Ogrodnik ◽

Wubin Xu

Keyword(s):

Journal Bearing ◽

System Stability ◽

Analysis Method ◽

Shape Distribution ◽

Hydrodynamic Journal Bearing ◽

The Stability ◽

Cylindricity Error ◽

Saddle Shape ◽

Fourier Model ◽

Bearing System

The present study investigates the effect of cylindricity error on the performance of hydrodynamic journal bearing systems. Two types of cylindricity errors of the journal, namely the drum shape distribution cylindricity error (DCE) and the saddle shape distribution cylindricity error (SCE), are considered. The Legendre–Fourier model is used to characterize the profile of each journal. Based on the nonlinear analysis method, the dynamic characteristics and stability of hydrodynamic journal bearing systems are analyzed. The results indicate that cylindricity error affects the system stability, and the effect is related to the type and level of the error. DCE used with a certain range of operating speed and load is not harmful and is even beneficial to the stability of hydrodynamic journal bearing systems; conversely, SCE decreases the system stability. When the Sommerfeld number is between 0.02 and 0.05, cylindricity errors have a minimal effect on the system stability. Additionally, the results indicate that the effect of cylindricity error on the bearing system is more significant than that of roundness error.

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