An Experimental Investigation on the Static and Dynamic Characteristics of Journal Bearings Under the Influence of Twisting Misalignment

1997 ◽  
Vol 119 (1) ◽  
pp. 188-192 ◽  
Author(s):  
P. Arumugam ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Finite Element Method ◽  
Vertical Direction ◽  
Journal Bearings ◽  
Response Functions ◽  
The Finite Element Method ◽  
Static And Dynamic Characteristics ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Different Levels ◽  
Bearing System

The misalignment between the journal and the bearing in a rotor-bearing system may be due to manufacturing error, elastic deflection, thermal expansion etc. In the present work, the eight linearized stiffness and damping coefficients of the cylindrical and three lobe bearings are identified at different levels of bearing misalignment (twisting misalignment) and at different speeds of the rotor. The identification method used here needs FRFs (Frequency Response Functions) obtained by the measurements and the finite element method. The twisting misalignment changes the stiffness and damping coefficients in the vertical and horizontal directions. In the case of three lobe bearings, for 0.7 degree of misalignment, the stiffness in the vertical direction is increased by about 12 percent.

Experimental Identification of Linearized Oil Film Coefficients of Cylindrical and Tilting Pad Bearings

1995 ◽  
Vol 117 (3) ◽  
pp. 593-599 ◽  
Author(s):  
P. Arumugam ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Journal Bearings ◽  
Response Functions ◽  
Flexible Rotor ◽  
The Finite Element Method ◽  
Theoretical Simulation ◽  
Oil Film ◽  
Damping Coefficients ◽  
Experimental Identification ◽  
Tilting Pad ◽  
Stiffness And Damping

The dynamic behavior of the rotating machinery supported by the hydrodynamic journal bearings is significantly influenced by the dynamic characteristics of the oil film. In the present work an efficient identification method is used to identify the stiffness and damping coefficients of the tilting pad and cylindrical journal bearings of a flexible rotor-bearing system. The method uses FRFs (Frequency Response Functions) obtained by the measurements and the finite element method. The accuracy and feasibility of the method were tested and demonstrated by theoretical simulation. The possible effects of oil-film inertia is also verified by the theoretical simulation. The method can be further extended to identify twelve linearized oil-film coefficients.

On the Choice of Element for Solving Lubrication Problems

1998 ◽  
Vol 120 (3) ◽  
pp. 636-639
Author(s):  
Ram Turaga ◽  
A. S. Sekhar ◽  
B. C. Majumdar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
High Eccentricity ◽  
Damping Coefficients ◽  
Significant Difference ◽  
The Stability ◽  
Stiffness And Damping ◽  
Element Method

This study deals with the stability characteristics of journal bearings using the finite element method. Two different elements, a 3-node linear triangle and a 6-node quadratic triangle, have been used. The results show a significant difference in (1) stiffness and damping coefficients and (2) stability characteristics at high eccentricity ratios due to the use of the two different elements.

scholarly journals Experimental Identification of Linearized Oil Film Coefficients of Cylindrical and Tilting Pad Bearings

1994 ◽  
Author(s):  
P. Arumugam ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Journal Bearings ◽  
Response Functions ◽  
Flexible Rotor ◽  
The Finite Element Method ◽  
Theoretical Simulation ◽  
Oil Film ◽  
Damping Coefficients ◽  
Experimental Identification ◽  
Tilting Pad ◽  
Stiffness And Damping

The dynamic behavior of the rotating machinery supported by the hydrodynamic journal bearings is significantly influenced by the dynamic characteristics of the oil-film. In the present work an efficient identification method is used to identify the stiffness and damping coefficients of the tilting pad and cylindrical journal bearings of flexible rotor-bearing system. The method uses FRFs (Frequency Response Functions) obtained by the measurements and the finite element method. The accuracy and feasibility of the method were tested and demonstrated by theoretical simulation. The possible effects of oil-film inertia is also verified by the theoretical simulation. The method can be further extended to identify twelve linearized oil-film coefficients.

Stability of Multirecess Hybrid-Operating Oil Journal Bearings

1985 ◽  
Vol 107 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Y. S. Chen ◽  
H. Y. Wu ◽  
P. L. Xie
Keyword(s):  
Finite Difference Method ◽  
Dynamic Performance ◽  
Journal Bearings ◽  
Design Parameters ◽  
Stability Threshold ◽  
Damping Coefficients ◽  
Hybrid Bearing ◽  
The Stability ◽  
Stiffness And Damping ◽  
Bearing System

An analysis and a numerical solution using finite difference method to predict the dynamic performance of multirecess hybrid-operating oil journal bearings are presented. The linearized stiffness and damping coefficients of a typical capillary-compensated bearing with four recesses are computed for various design parameters. The corresponding stiffness and the stability threshold of the bearing are then obtained, and the opposite influences of the hydrodynamic action on them are demonstrated. The effect of rotor flexibility on the onset of self-excited whirl is discussed, and a method is given to determine the stability threshold of a rotor-hybrid bearing system.

scholarly journals Bifurcation analysis of rotor/bearing system using third-order journal bearing stiffness and damping coefficients

2021 ◽  
Author(s):  
T. A. El-Sayed ◽  
Hussein Sayed
Keyword(s):  
Equations Of Motion ◽  
Journal Bearings ◽  
Third Order ◽  
Damping Coefficients ◽  
The Third ◽  
Rotor Bearing ◽  
Bearing Stiffness ◽  
Rotor Stiffness ◽  
Stiffness And Damping ◽  
Bearing System

AbstractHydrodynamic journal bearings are used in many applications which involve high speeds and loads. However, they are susceptible to oil whirl instability, which may cause bearing failure. In this work, a flexible Jeffcott rotor supported by two identical journal bearings is used to investigate the stability and bifurcations of rotor bearing system. Since a closed form for the finite bearing forces is not exist, nonlinear bearing stiffness and damping coefficients are used to represent the bearing forces. The bearing forces are approximated to the third order using Taylor expansion, and infinitesimal perturbation method is used to evaluate the nonlinear bearing coefficients. The mesh sensitivity on the bearing coefficients is investigated. Then, the equations of motion based on bearing coefficients are used to investigate the dynamics and stability of the rotor-bearing system. The effect of rotor stiffness ratio and applied load on the Hopf bifurcation stability and limit cycle continuation of the system are investigated. The results of this work show that evaluating the bearing forces using Taylor’s expansion up to the third-order bearing coefficients can be used to profoundly investigate the rich dynamics of rotor-bearing systems.

Static and dynamic characteristics and stability analysis of high-speed water-lubricated hydrodynamic journal bearings

2021 ◽  
pp. 135065012110270
Author(s):  
Bo Xu ◽  
Hun Guo ◽  
Xiaofeng Wu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Inertia Effect ◽  
Static And Dynamic Characteristics ◽  
Damping Coefficients ◽  
Stiffness And Damping

The purpose of this paper is to analyze the influence of turbulent, inertia, and misaligned effects on the static and dynamic characteristics and stability of high-speed water-lubricated hydrodynamic journal bearings. Based on the Navier–Stokes equation, the mixing-length theory, and the essential assumption that the velocity profile is not strongly affected by inertia force, the fluid lubrication model with turbulent, inertia, and misaligned effects is established, and then the stability analysis of bearings is carried out based on the equation of motion with four degrees of freedom. The model is solved by the finite difference method and the numerical results are compared under different operating conditions. The results show that the turbulent effect greatly increases the load capacity, power consumption, stiffness and damping coefficients, and stability of bearings, and the inertia effect significantly increases the volume flow rate of bearings, and the misaligned effect increases the load capacity, stiffness and damping coefficients, and stability of bearings. In high rotary speed and moderate eccentricity ratios, the influence of the inertia effect on the load capacity, stiffness coefficients, and stability cannot be neglected.

scholarly journals Finite Element Analysis of the Multilayered Honeycomb Composite Material Subjected to Impact Loading

2017 ◽  
Vol 54 (1) ◽  
pp. 180-179 ◽  
Author(s):  
Raul Cormos ◽  
Horia Petrescu ◽  
Anton Hadar ◽  
Gorge Mihail Adir ◽  
Horia Gheorghiu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Experimental Testing ◽  
Finite Element Models ◽  
The Finite Element Method ◽  
Low Velocity ◽  
Element Analysis ◽  
Element Simulation ◽  
Different Levels

The main purpose of this paper is the study the behavior of four multilayered composite material configurations subjected to different levels of low velocity impacts, in the linear elastc domain of the materials, using experimental testing and finite element simulation. The experimental results obtained after testing, are used to validate the finite element models of the four composite multilayered honeycomb structures, which makes possible the study, using only the finite element method, of these composite materials for a give application.

scholarly journals Analysis of the effect of oil inlet size on the static performance characteristics of non-Newtonian lubricated hole-entry hybrid journal bearings

2021 ◽  
Vol 37 ◽  
pp. 522-531
Author(s):  
Haiyin Cao ◽  
Yu Huang ◽  
Youmin Rong ◽  
Hao Wu ◽  
Minghui Guo
Keyword(s):  
Finite Element Method ◽  
High Speed ◽  
Reynolds Equation ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Power Law Model ◽  
The Finite Element Method ◽  
Solution Strategy ◽  
Nonuniform Mesh ◽  
Static Performance

Abstract In this study, the influence of inlet pocket size on the static performance of non-Newtonian lubricated hole-entry hybrid journal bearings is theoretically analyzed. The oil film of the bearing is discretized into a nonuniform mesh containing the geometric characteristics of the oil inlet pocket, and the inlet pocket is treated as a micro-oil recess. The Reynolds equation is solved by the finite element method based on Galerkin's techniques, and a new solution strategy to solve the recess/pocket pressure is proposed. The power-law model is used to introduce the non-Newtonian effect. The results show that the static performance characteristics of this type of bearing are greatly affected by the pocket size at both zero speed and high speed.

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