Solution of the Stability Problem for 360 Deg Self-Acting, Gas-Lubricated Bearings

1965 ◽  
Vol 87 (1) ◽  
pp. 199-210 ◽  
Author(s):  
V. Castelli ◽  
H. G. Elrod
Keyword(s):  
Stability Problem ◽  
Journal Bearing ◽  
Infinite Length ◽  
The Stability

This is an investigation of the stability of self-acting, gas-lubricating bearings. Two approaches to the solution are presented and their results are compared. Also, the relation is discussed between the present work and other, more simplified, methods available in the literature. The particular case of a 360 deg journal bearing of infinite length is treated, and the changes necessary to use the same theories with other geometries are pointed out.

Stability of a Squeeze-Film Journal Bearing

1967 ◽  
Vol 89 (3) ◽  
pp. 369-373 ◽  
Author(s):  
J. V. Beck ◽  
C. L. Strodtman
Keyword(s):  
Journal Bearing ◽  
Mathieu Equation ◽  
Squeeze Film ◽  
Infinite Length ◽  
Driving Frequency ◽  
Numerical Techniques ◽  
Variational Techniques ◽  
Regions Of Stability ◽  
The Stability ◽  
Stability Limits

An investigation is made of the regions of stability for a compressible fluid, squeeze-film journal bearing of infinite length. Motion along one axis considered and the resulting dynamic equation is solved two ways: by variational techniques and by numerical techniques. The solution from the variational analysis can be approximated by a Mathieu equation thus showing that instability can occur at one-half the driving frequency. The numerical analysis shows the stability limits in terms of the load, drive amplitude, and dimensionless “mass.” The stability analysis is significant as there appears to be a rather large number of combinations of the parameters for which the squeeze-film journal is not stable. The stability characteristics of a squeeze-film bearing should, therefore, be examined carefully before application.

scholarly journals The two-dimensional hydrodynamical theory of moving aerofoils. IV

1947 ◽  
Vol 188 (1015) ◽  
pp. 439-463
Keyword(s):  
Stability Problem ◽  
Two Dimensional ◽  
Centre Of Gravity ◽  
First Approximation ◽  
Von Karman ◽  
Moving Cylinder ◽  
Period Equation ◽  
The Stability ◽  
Von Kármán ◽  
Hydrodynamical Theory

In the first part of this paper opportunity has been taken to make some adjustments in certain general formulae of previous papers, the necessity for which appeared in discussions with other workers on this subject. The general results thus amended are then applied to a general discussion of the stability problem including the effect of the trailing wake which was deliberately excluded in the previous paper. The general conclusion is that to a first approximation the wake, as usually assumed, has little or no effect on the reality of the roots of the period equation, but that it may introduce instability of the oscillations, if the centre of gravity of the element is not sufficiently far forward. During the discussion contact is made with certain partial results recently obtained by von Karman and Sears, which are shown to be particular cases of the general formulae. An Appendix is also added containing certain results on the motion of a vortex behind a moving cylinder, which were obtained to justify certain of the assumptions underlying the trail theory.

Some Structural Properties of Systolic Tree Automata

1989 ◽  
Vol 12 (4) ◽  
pp. 571-585
Author(s):  
E. Fachini ◽  
A. Maggiolo Schettini ◽  
G. Resta ◽  
D. Sangiorgi
Keyword(s):  
Structural Properties ◽  
Stability Problem ◽  
Sufficient Condition ◽  
Tree Automata ◽  
Necessary And Sufficient Condition ◽  
The Stability ◽  
Necessary And Sufficient

We prove that the classes of languages accepted by systolic automata over t-ary trees (t-STA) are always either equal or incomparable if one varies t. We introduce systolic tree automata with base (T(b)-STA), a subclass of STA with interesting properties of modularity, and we give a necessary and sufficient condition for the equivalence between a T(b)-STA and a t-STA, for a given base b. Finally, we show that the stability problem for T(b)-ST A is decidible.

A constructive method for the solution of the stability problem

1970 ◽  
Vol 16 (1) ◽  
pp. 1-7 ◽  
Author(s):  
James Lucien Howland ◽  
John Albert Senez
Keyword(s):  
Stability Problem ◽  
Constructive Method ◽  
The Stability

Design of Hydraulic Descaling Computer Control System

2014 ◽  
Vol 608-609 ◽  
pp. 19-22
Author(s):  
Ping Xu ◽  
Jian Gang Yi
Keyword(s):  
Control System ◽  
Stability Problem ◽  
Computer Control ◽  
Control Methods ◽  
Computer Control System ◽  
Control Software ◽  
Pressure Water ◽  
Working Principle ◽  
The Stability

Hydraulic descaling system is the key device to ensure the surface quality of billet. However, traditional control methods lead to the stability problem in hydraulic descaling system. To solve the problem, the construction of the hydraulic descaling computer control system is studied, the working principle of the system is analyzed, and the high pressure water bench of hydraulic descaling is designed. Based on it, the corresponding computer control software is developed. The application shows that the designed system is stable in practice, which is helpful for enterprise production.

Investigation of sustainability of lubricated journal bearing under relevant design parameters

2018 ◽  
Vol 70 (4) ◽  
pp. 789-804 ◽  
Author(s):  
M.M. Shahin ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Md. Arefin Kowser ◽  
Uttam Kumar Debnath ◽  
M.H. Monir
Keyword(s):  
Aspect Ratio ◽  
Elastic Strain ◽  
Journal Bearing ◽  
Design Parameters ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Formation ◽  
Bearing Design ◽  
The Stability ◽  
Bearing Friction

Purpose The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation. Design/methodology/approach A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance. Findings An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil. Originality/value It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

A novel approach for the stability problem in non-linear dynamical systems

2003 ◽  
Vol 155 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Tarcı́sio M. Rocha Filho ◽  
Iram M. Gléria ◽  
Annibal Figueiredo
Keyword(s):  
Dynamical Systems ◽  
Stability Problem ◽  
Linear Dynamical Systems ◽  
Novel Approach ◽  
Non Linear ◽  
The Stability
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