Effect of Texture Region on the Static and Dynamic Characteristic of Partially Textured Journal Bearings

2018 ◽  
pp. 422-436
Author(s):  
Hiroo Taura
Keyword(s):  
Dynamic Characteristic ◽  
Journal Bearings ◽  
Texture Region

Static and stability analysis of partial slip texture multi-lobe journal bearings

2019 ◽  
Vol 234 (4) ◽  
pp. 567-587
Author(s):  
TVVLN Rao ◽  
Ahmad M A Rani ◽  
Norani M Mohamed ◽  
Hamdan H Ya ◽  
Mokhtar Awang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Partial Slip ◽  
Pressure Gradients ◽  
Capacity Coefficient ◽  
Texture Region ◽  
Linearized Stability ◽  
Infinitesimal Perturbation

This paper presents one-dimensional analysis of modified dynamic Reynolds equation derived for partial slip texture multi-lobe journal bearings. The novelty included in this study is the configuration of partial slip texture region on the bottom bearing lobe surface of a multi-lobe journal bearing under a constant vertical load. The nondimensional pressure and shear stress for steady-state and nondimensional pressure gradients for dynamic coefficients for each lobe with partial slip texture configuration are derived based on narrow groove theory. Linearized stability analysis is evaluated using infinitesimal perturbation method. Results of static and stability characteristics of partial slip texture multi-lobe (two-axial groove, elliptical, three-lobe and offset) journal bearings are presented. Partial slip texture configuration significantly enhances load capacity, coefficient of friction, and stability of two-lobe journal bearing.

An Application of Short Bearing Theory to Dynamic Characteristic Problems of Turbulent Journal Bearings

1987 ◽  
Vol 109 (2) ◽  
pp. 307-314 ◽  
Author(s):  
Hiromu Hashimoto ◽  
Sanae Wada ◽  
Jin-ichi Ito
Keyword(s):  
Dynamic Characteristic ◽  
Equations Of Motion ◽  
Computation Time ◽  
Journal Bearings ◽  
Oil Film ◽  
Euler’S Method ◽  
Linearized Stability ◽  
Rotor Bearing ◽  
Time Required ◽  
Nonlinear Equations Of Motion

The dynamic characteristic problems of turbulent journal bearings are theoretically analyzed. The oil film forces considering the turbulent effects are analytically obtained under the short bearing assumption. The linearized stability analysis is developed for a perfectly rigid rotor supported horizontally in the two identical aligned oil film journal bearings and the whirl onset velocities for rotor-bearing systems are determined for various Reynolds numbers. In addition, the nonlinear equations of motion for rotor-bearing systems are solved by the improved Euler’s method and the journal center trajectories are examined for both cases with and without out-of-balance forces. The results obtained from the short bearing theory are compared with those from the finite bearing theory for the length-to-diameter ratio λ = 0.25 and 0.5. It is found that the turbulence has significant effects on the dynamic behavior of rotor-bearing systems and the short bearing theory has an advantage of reducing a computation time required for the calculation of journal center trajectories with an acceptable accuracy.

Dynamic Characteristic of Multirecess Externally Pressurized Oil Journal Bearing

1978 ◽  
Vol 100 (4) ◽  
pp. 467-471 ◽  
Author(s):  
M. K. Ghosh
Keyword(s):  
Perturbation Theory ◽  
Theoretical Analysis ◽  
Dynamic Characteristic ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Harmonic Vibrations ◽  
Damping Characteristics ◽  
Stiffness And Damping ◽  
Generalized Reynolds Equation

This paper describes a theoretical analysis of the dynamic behavior of multirecess externally pressurized oil journal bearings for a nonrotating journal subjected to plane harmonic vibrations. The generalized Reynolds’ equation for a finite bearing has been solved using perturbation theory. Stiffness and damping characteristics of a capillary compensated bearing are given.

Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Characteristic ◽  
Driving Force ◽  
Magnetic Circuit ◽  
Response Speed ◽  
Computation Method ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.

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