Numerical analysis of the transient wear and lubrication behaviors of misaligned journal bearings caused by linear shaft misalignment

2021 ◽  
pp. 1-17
Author(s):  
Tianyou Yang ◽  
Yanfeng Han ◽  
Yijia Wang ◽  
Guo Xiang
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Contact Pressure ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Fluid Pressure ◽  
Axial Direction ◽  
Wear Depth ◽  
Wear Process ◽  
Journal Misalignment

Abstract The purpose of this study is to investigate the role of the misalignment journal, caused by journal elastic deformation, on the transient wear and mixed lubrication performances using a numerical model. In the numerical model, the transient geometry lubrication clearance considering the journal misalignment, the transient elastic deformation and the transient wear depth are incorporated to evaluate the transient film thickness during wear process. The evolutions, under different external loads, of the wear depth, wear rate, elastic deformation, film thickness, fluid pressure and contact pressure are calculated by the numerical model. Furthermore, the calculated results of the misaligned journal bearing are compared with those of the aligned journal bearing. The results show that the distributions of the wear depth, film pressure and elastic deformation are asymmetric along the axial direction and the peak values of them shift toward the back end when the journal misalignment is considered. The maximum wear depth, maximum fluid pressure, maximum contact pressure and maximum elastic deformation of the misaligned journal condition are significantly larger than those of the aligned journal condition.

Oil film thickness analysis of the sealing surface for hydraulic rotary rectangular vane actuator

2018 ◽  
Vol 70 (8) ◽  
pp. 1494-1499
Author(s):  
Han Qing ◽  
LiangXi Xie ◽  
Lu Li ◽  
Chuang Jia
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Contact Pressure ◽  
Reynolds Equation ◽  
Distribution Curve ◽  
Contact Pressure Distribution ◽  
Content Type ◽  
Oil Film ◽  
Rotary Actuator ◽  
The Relationship

Purpose This paper aims to establish a numerical model to calculate contact pressure for rectangular vane sealing surface of hydraulic rotary actuator. Numerical model can be applied to solve the steady-state Reynolds equation after the oil film thickness and the contact pressure distribution curve of the vane sealing surface are obtained. Design/methodology/approach The authors established the numerical model of contact pressure base on the theory of elastic after, the Reynolds equation is solved by the inverse solution. Findings The relationship between the oil film thickness of vane sealing surface and the contact pressure on different sealing location for hydraulic rotary actuator is obtained. At the same time, the lubrication state on the surface of seal is also found when the hydraulic rotary actuator runs stably. Originality/value The study shows that the lubricating state of the vane sealing surface is mixed lubrication, when the rotor of the hydraulic rotary actuator is running stably at a certain speed. Meanwhile, this research will provide a theory basis for later experiment for the hydraulic rotary vane actuator.

Research on the Static and Dynamic Characteristics of Misaligned Journal Bearing Considering the Turbulent and Thermohydrodynamic Effects

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Guohui Xu ◽  
Jian Zhou ◽  
Haipeng Geng ◽  
Mingjian Lu ◽  
Lihua Yang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Journal Misalignment ◽  
Oil Film Pressure

Journal misalignment usually exists in journal bearings that affect nearly all the bearings static and dynamic characteristics including minimum oil film thickness, maximum oil film pressure, maximum oil film temperature, oil film stiffness, and damping. The main point in this study is to provide a comprehensive analysis on the oil film pressure, oil film temperature, oil film thickness, load-carrying capacity, oil film stiffness, and damping of journal bearing with different misalignment ratios and appropriately considering the turbulent and thermo effects based on solving the generalized Reynolds equation and energy equation. The results indicate that the oil thermo effects have a significant effect on the lubrication of misaligned journal bearings under large eccentricity ratio. The turbulent will obviously affect the lubrication of misaligned journal bearings when the eccentricity or misalignment ratio is large. In the present design of the journal bearing, the load and speed become higher and higher, and the eccentricity and misalignment ratio are usually large in the operating conditions. Therefore, it is necessary to take the effects of journal misalignment, turbulent, and thermal effect into account in the design and analysis of journal bearings.

MechanicalModeling of the 2D Interfacial Slurry Pressure in CMP

2003 ◽  
Vol 767 ◽  
Author(s):  
C. Fred Higgs ◽  
Sum Huan Ng ◽  
Inho Yoon ◽  
Lei Shan ◽  
Lipkong Yap ◽  
...  
Keyword(s):  
Film Thickness ◽  
Contact Pressure ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Reynolds Equation ◽  
Removal Rate ◽  
Fluid Pressure ◽  
Equilibrium Analysis ◽  
Equation Modeling ◽  
Superposition Method

Chemical mechanical polishing (CMP) is a manufacturing process used to remove or planarize metallic, dielectric, or barrier layers on silicon wafers. During polishing, a wafer is pressed against an elastic pad that is flooded with slurry. Prior work has shown that an asymmetrical, subambient pressure develops at the interface between the silicon and the pad during polishing. Since the slurry pressure is on the order of the wafer-on-pad contact stress, the total contact pressure is asymmetrical. This promotes a non-uniform polishing rate, since Preston's equation states that the material removal rate is proportional to the total contact pressure. In order to determine the total contact pressure, experiments were conducted to measure the two-dimensional fluid pressure. A superposition method was then employed to calculate the slurry film thickness by performing an equilibrium analysis of the forces and moments created by the fluid and solid interactions. The film thickness obtained by this method is used to model the slurry pressure using the polar Reynolds' equation. Modeling results qualitatively agree with experiments.

Parametric and Controllable Shape Model of the Water-Lubricated Rubber Journal Bearing

2012 ◽  
Vol 455-456 ◽  
pp. 1468-1473
Author(s):  
Xiao Ping Pang ◽  
Jin Chen ◽  
Jia Xu Wang ◽  
Yi Hou
Keyword(s):  
Film Thickness ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Coupling Effect ◽  
Load Capacity ◽  
Deformation Effect ◽  
Shape Model ◽  
The Relationship

This paper describes a general bearing profile for the water-lubricated rubber journal bearing. Characteristics of the most popular water-lubricated rubber journal bearing, the straight fluted bearing, were deeply analyzed. The bearing profile was expressed using subsection function and a parametric and controllable shape model was built. By adjusting the parameters of the shape model, the existing bearing profiles can be integrated into the shape model and some bran-new bearing profile can be generated from the model. The rigid film thickness equation was achieved using the shape model and the relationship between the load capacity and the parameters of the shape model was established with the neglecting of elastic deformation effect. It is seen that the dimensionless load capacity reduces with the increase of the transition arc radius, the flute radius and the number of flutes,. The Necessity of the research on the bearing profile and the correctness of the shape model are validated. The parametric and controllable shape model is the foundation to study the fluid-solid coupling effect and to carry out the multi-disciplinary cooperating optimization for the water-lubricated rubber journal bearing.

Characteristic Analysis of Aircraft Glyd-Ring Seal Based on Mixed Lubrication Model

2020 ◽  
Author(s):  
Wang Wei ◽  
Wenjian Xiao ◽  
Xiaoping Ouyang ◽  
Shengrong Guo ◽  
Huayong Yang
Keyword(s):  
Film Thickness ◽  
Contact Pressure ◽  
Frictional Force ◽  
Fluid Pressure ◽  
Mixed Lubrication ◽  
Fluid Film ◽  
Characteristic Analysis ◽  
Piston Seal ◽  
Static Contact ◽  
Ring Seal

Abstract Reciprocating seals are vital components in hydraulic systems. As a kind of reciprocating seal, the glyd-ring is commonly used as a piston seal. For the sealing characteristics of aircraft glyd-ring under severe working conditions, systematic research and experimental verification are not sufficient. The liquid-solid coupling model based on mixed lubrication theory is established in order to analyze the characteristics of the glyd-ring seal in the cylinder piston. The contact stress distribution on the glyd-ring under different fluid pressures or temperatures is discussed through finite element analysis. The mechanical analysis of solids and fluids are carried out separately, and the thickness of the fluid film is continuously updated until the results of the deformation analysis converged. According to the calculation results obtained by this model, three characteristics of the glyd-ring seal (static contact pressure, film thickness, friction force) are discussed. As the fluid pressure rises, the contact pressure in the sealing area increases by a rate which is greater than that of the corresponding fluid pressure, the seal length is shortened, the fluid film thickness is reduced, and the frictional force gradually increases, this force increase is proved by test data. As the temperature rises, the contact pressure in the seal area (near the O-ring) increases by a rate which is greater than that of the corresponding fluid pressure, the seal length increases, the oil film thickness decreases, and the frictional force increases significantly.

Study on 3D Shape Optimization for Hydrodynamic Journal Bearing Using Goal Attainment Multi-Objective Function

2013 ◽  
Vol 319 ◽  
pp. 505-509 ◽  
Author(s):  
Xiao Ping Pang ◽  
Jin Chen
Keyword(s):  
Film Thickness ◽  
Shape Optimization ◽  
Goal Attainment ◽  
Journal Bearing ◽  
Load Capacity ◽  
Axial Direction ◽  
Three Dimensions ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Hydrodynamic Journal Bearing

This paper is focused on multi-objective optimization to find the best performance related to the geometrical design of the hydrodynamic journal bearing in three dimensions 3D. The mathematical model for 3D film thickness profile was driven using Fourier’s series function and axial waviness value to represent in circumferential and axial direction respectively. A Goal attainment function was used as an optimization tool with goals to minimize the power loss and side leakage and to maximize the load capacity, while the amplitude (a), number of wave (m) and Fourier's series coefficients of the general film thickness were taken as design variables subjected to several bounds and constraints. The optimized results show the cylindrical plain bearing is the best to load capacity due to changing the axial shape does not enhance the load capacity without violation of the minimum film thickness. Comparison was made between goal attainment multi-objective optimization and GA single-objective optimization. The new method for shape optimization based on 3D general film thickness is more evident than GA.

Numerical Model of Journal Bearing Lubrication Considering a Bending Stiffness Effect

2013 ◽  
Vol 284-287 ◽  
pp. 854-860
Author(s):  
Juh Wan Choi ◽  
Seong Su Kim ◽  
Sung Soo Rhim ◽  
Jin Hwan Choi
Keyword(s):  
Numerical Model ◽  
Film Thickness ◽  
Journal Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Bending Stiffness ◽  
Thickness Variation ◽  
Lubrication System ◽  
Film Pressure ◽  
Oil Film ◽  
Oil Film Pressure

An analysis for operating characteristics of journal bearing lubrication system is performed based on the numerical model. Dynamic bearing lubrication characteristics such as oil film pressure and thickness distribution can be analyzed through a numerical model with an integration of elastohydrodynamics and multi-flexible-body dynamics (MFBD). In particular, the oil film thickness variation by elastic deformation is considered in the elastohydrodynamic analysis by applying the bending stiffness effect of journal. And the oil film thickness variation by the bending stiffness effect is applied to the fluid governing equations to calculate the oil film pressure in the elastohydrodynamic lubrication region. A series of process proposed in this study is available for the analysis of realistic elastohydrodynamic lubrication phenomenon. Also, a numerical example for the journal bearing lubrication system is demonstrated and compared with the experimental results. The numerical results considering the bending stiffness effect show a good agreement with the experimental results.

Effect of journal misalignment on the static characteristics of an innovative journal bearing with adjustable elements in load-on-pad and load-between-pad configurations

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
H. Girish ◽  
Raghuvir Pai
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Content Type ◽  
Load Carrying ◽  
Bearing Load ◽  
Minimum Film Thickness ◽  
Peak Pressures ◽  
Journal Misalignment

Purpose The purpose of this paper is to theoretically analyze an innovative form of variable bearing configuration having four pads with unique adjustability principle operated under journal misaligned conditions. The parameters such as load positions, degrees of misalignment (DM) and pad adjustment configurations influencing the steady-state performance of the four-pad adjustable bearing are detailed in this paper. Design/methodology/approach The proposed adjustable pad geometry possesses the ability to undergo radial and tilt motions in both inward and outward directions. Analysis is carried out by considering journal misalignment in vertical and horizontal planes with bearing modelled for load-on-pad and load-between-pad configurations. The film thickness equation derived to incorporate the radial and tilt adjustment parameters is further modified to accommodate the different load orientations and misaligned journal conditions. The pressure field equation is solved by applying finite-difference technique combined with Gauss Siedel iterative method. Findings At higher DM, peak pressures generated in the minimum film thickness region near the pad ends highly influences the bearing load carrying capacity. Results indicated that the adjustable four-pad bearing geometry is highly efficient in withstanding the journal misalignment by radially displacing and tilting the four pads in negative directions. Originality/value For bearing designers, this research highlights the importance of considering the misalignment factor during the design stages of an adjustable journal bearing. The proposed adjustability concept is proven to be effective enough to improve the bearing performance and, in turn, withstand the journal misalignment.

Influence of Journal Misalignment Caused by Shaft Deformation under Rotational Load on Performance of Journal Bearing

2005 ◽  
Vol 219 (4) ◽  
pp. 275-283 ◽  
Author(s):  
Jun Sun ◽  
Changlin Gui ◽  
Zhiyuan Li ◽  
Zhen Li
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Journal Bearing ◽  
Film Pressure ◽  
Lubrication Performance ◽  
Rotating Load ◽  
Rotational Load ◽  
Journal Misalignment ◽  
Shaft Deformation ◽  
Bearing System

A method to analyse lubrication performance of journal bearing considering journal misalignment caused by shaft deformation under rotating load in a shaft-bearing system was established and validated by special experiments on a developed experimental rig of journal bearing. The experimental results show that the proposed analytical formulation and method can meet the researching requirements. Oil film pressure, end leakage flowrate, and friction coefficient of journal bearing at variant journal misalignment caused by shaft deformation under rotating load were calculated. The results show that journal misalignment makes obvious difference to distribution of film pressure and film thickness. The maximum film pressure increases markedly. The minimum film thickness reduces. End leakage flowrate increases. Friction coefficient of journal slightly changes. Therefore, in order to make the calculation of journal bearing more realistic and to achieve more reasonable design in shaft-bearing system, the influence of shaft deformation under load should be considered in lubrication analysis of journal bearing in a shaft-bearing system.

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