Research on shaft strength considering offsetting distribution of film pressure of journal bearing in shaft-bearing system

2007 ◽  
Vol 221 (1) ◽  
pp. 99-107 ◽  
Author(s):  
S Jun ◽  
G Changlin ◽  
W Jingfeng
Keyword(s):  
Stress Distribution ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Direct Interaction ◽  
Present Calculation ◽  
Design Calculation ◽  
Film Pressure ◽  
Lubrication Characteristics ◽  
Strength And Stiffness ◽  
Bearing System

There is a direct interaction between shaft and bearing in shaft-bearing system. The effect of lubrication status of bearing was not considered in the present calculation of shaft strength. In this paper, shaft-bearing system was taken as the study object. Hydrodynamic lubrication characteristics of a journal bearing considering misalignment caused by shaft deformation in shaft-bearing system were analysed. There are obvious offsetting distribution of film pressure and increase of the highest film pressure when journal misalignment takes place. Based on the lubrication analysis of bearing, the stress distribution of shaft was calculated when the film pressure calculated was used as boundary condition of load. The results show that there are obvious changes of stress distribution and great increase of stress near the area on shaft where it is acted upon the highest film pressure when considering the offsetting distribution of film pressure. The shaft strength is affected remarkably. Therefore, in order to accord with the tendency today for high precision in the design calculation, thus more reasonable design can be acquired, the coupling between the analysis of bearing tribology and the analysis of strength and stiffness of shaft must be studied in the design of shaft-bearing system.

scholarly journals Effect of the axial movement of misaligned journal on the performance of hydrodynamic lubrication journal bearing with rough surface

2019 ◽  
Vol 20 (4) ◽  
pp. 402 ◽  
Author(s):  
Biao Li ◽  
Jun Sun ◽  
Shaoyu Zhu ◽  
Yangyang Fu ◽  
Xiaoyong Zhao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Reynolds Equation ◽  
Working Condition ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Axial Movement ◽  
Combined Action ◽  
Lubrication Characteristics ◽  
Bearing System

Generally, the movement of journal along the direction of bearing axis under the combined action of various factors is neglected in the lubrication study of bearing, which is quite different from the actual working condition of bearing in the shaft-bearing system. In this paper, with a comprehensive consideration of the axial movement of journal, the surface topography of journal and bearing and the misalignment of journal, a new model about the hydrodynamic lubrication of misaligned journal bearing is established based on the average Reynolds equation. Considering the effect of the axial movement of misaligned journal, the lubrication characteristics parameters of rough journal bearing is presented and mainly discussed. The results show that the axial movement of misaligned journal has a distinct effect on the bearing lubrication characteristics. The influence of the axial movement of misaligned journal on the bearing lubrication characteristics is slightly reduced when considering the surface roughness.

Non-Linear Unstability Model and Analysis of the Engine Main Journal Bearing

2012 ◽  
Vol 246-247 ◽  
pp. 790-794
Author(s):  
Kang Shao ◽  
Chang Wen Liu ◽  
Feng Rong Bi ◽  
Xia Wang ◽  
Jian Zhang
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Main Bearing ◽  
Linear Effect ◽  
Non Linear ◽  
The Finite Difference Method ◽  
Engine Crankshaft ◽  
Bearing System ◽  
Oil Film Pressure

On the base of Reynolds equation, the dynamic load of an engine crankshaft main journal bearing system is studied. The oil film pressure is solved from the non-Newtonian Reynolds equation with non-linear model of a finite length journal bearing. The flexible crankshaft is coupling with hydrodynamic lubrication of bearing film. The elastohydrodynamic bearing is treated as non-linear bearing with the finite difference method when considered the unstability load that was acted on the main journal. This paper aims to identify the non-linear effect of engine main bearing in the case of unstability load.

Journal Bearing Rotor Speed Effect on Dynamics Coefficients and Film Pressure

2013 ◽  
Vol 274 ◽  
pp. 320-323
Author(s):  
Nai Wen Hu ◽  
Guang Bin Yu ◽  
Xue Mei Wu ◽  
Chang Sheng Hu ◽  
Zhi Gang Qu ◽  
...  
Keyword(s):  
Thermal Instability ◽  
Journal Bearing ◽  
Pressure Effect ◽  
Rotor Speed ◽  
Film Pressure ◽  
Dynamic Coefficients ◽  
Rotor Bearing ◽  
Speed Effect ◽  
Analytical Expressions ◽  
Bearing System

The dynamic coefficients and film pressure effect in rotor-bearing systems may lead to an unstable station. The mechanism of the dynamic coefficients and film pressure induced thermal instability in the rotor-bearing system has been studied. The journal bearing model is adopted for the derivation of analytical expressions. The results show that the rotor speed has some effect on bearing dynamic coefficients and film pressure.

Research on Energy Equation of Lubrication Model on Large-Scale Journal Bearing System

2010 ◽  
Vol 145 ◽  
pp. 139-144
Author(s):  
Jian Mei Wang ◽  
Qing Xue Huang ◽  
Jian Feng Kang ◽  
Yang Fan
Keyword(s):  
Service Life ◽  
Large Scale ◽  
Energy Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Journal Bearings ◽  
Calculation Results ◽  
Major Factors ◽  
Energy Equations ◽  
Bearing System

To prolong the service life of large-scale journal bearings, the major factors that have influences on bearing performances should be taken into account. By consideration of the variations of viscosity and density with pressure and temperature, a more thorough thermo-hydrodynamic lubrication model was established. With designation of variables with nondimensional parameters, a series of equations were nondimensionied, and the corresponding energy equations at different oil-film layers and boundaries were obtained respectively according to proper difference formats, and then solved by the integration of Finite Difference Method (FDM) with Boundary Element Method (BEM). Calculation results have proved that such complete mathematical model could provide great theoretical guide meaning to improve the lubrication performances and to prolong the service life of contact components of heavy journal bearings.

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.

Effect of Lubrication Status of Bearing on Crankshaft Strength

2007 ◽  
Vol 129 (4) ◽  
pp. 887-894 ◽  
Author(s):  
Jun Sun ◽  
Changlin Gui
Keyword(s):  
Combustion Engine ◽  
Direct Interaction ◽  
Local Area ◽  
Present Calculation ◽  
The Finite Element Method ◽  
Film Pressure ◽  
Oil Film ◽  
Bearing Load ◽  
Oil Film Pressure ◽  
Element Method

There is direct interaction between crankshaft and bearing in an internal combustion engine. The effect of lubrication status of bearing was not considered in the present calculation of crankshaft strength. A given oil film pressure distribution of bearing was generally used as load acted on journal. In this paper, a crankshaft-bearing system was taken as the study object. On the basis of lubrication analysis of misaligned bearing caused by crankshaft deformation, the stress and strength of-crankshaft were calculated using analytical oil film pressure of bearing as the load boundary condition. Crankshaft deformation and bearing load were calculated by whole crankshaft beam-element method. The lubrication of crankshaft bearing was analyzed by the kinetics method. Crankshaft stress was calculated by the finite-element method. The results show that when the effect of crankshaft deformation under load is considered, the offset distribution of oil film pressure of bearing appears and the highest oil film pressure increases remarkably, which result in the stresses of local area on fillet surface of crankshaft journal increase obviously and the safety factor of crankshaft decreases.

Transient Analysis of the Textured Journal Bearing Operating With the Piezoviscous and Shear-Thinning Fluids

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Di Zhang ◽  
Youbai Xie
Keyword(s):  
Transient Analysis ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Shear Thinning ◽  
Lubrication Regimes ◽  
Shear Thinning Fluids ◽  
Lubrication Regime ◽  
Start Up ◽  
Metal Metal ◽  
Bearing System

In this paper, a mixed lubrication model is presented to analyze the tribological behavior of the textured journal bearings operating from mixed to hydrodynamic lubrication regimes. In particular, the effects of fluid piezoviscosity and the non-Newtonian fluid behavior are also considered. The presented model solves the hydrodynamic lubrication problem by a mass-conserving formation of the Reynolds equation, whereas the metal–metal contact is considered by using the Greenwood and Tripp (GT) contact model which is linked with the hydrodynamic model based on the concept of Johnson's load sharing. As a result, the performance of the textured journal bearing system under different lubrication regimes, including boundary lubrication regime, mixed hydrodynamic lubrication regime, and hydrodynamic lubrication regime, can be evaluated. Using the journal bearing systems operated under the start-up condition as examples, prediction demonstrates the influences of texture distributions on friction and wear. It is found that the friction reducing effect induced by texturing is influenced by the distribution of the texturing zones. In particular, the hydrodynamic friction can be reduced when the eccentricity ratio is changed from high to low. Moreover, it appears that the shear-thinning effect of lubricant cannot be neglected in the transient analysis of journal bearing system.

Experimental Study of Oil Supply Pressure Effects on Bearing Friction in Hydrodynamic Lubrication

2013 ◽  
Vol 315 ◽  
pp. 977-981 ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
Rob Dwyer-Joyce
Keyword(s):  
Friction Coefficient ◽  
Frictional Force ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Diameter Ratio ◽  
Pressure Effects ◽  
Oil Supply ◽  
Supply Pressure ◽  
Bearing System ◽  
Bearing Friction

Journal bearing is widely applied in most of rotating machineries for transmission of large loads at mean speed of rotation. Friction caused by the shearing condition between journal, bearing and lubricant contribute to power loses in journal bearing system. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on frictional force, friction coefficient and torque of a journal bearing. A journal diameter of 100 mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 MPa). Frictional force and friction coefficient results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the change in oil supply pressure has affected the fluid frictional force and friction coefficient to some extent.

Application of Computational Fluid Dynamics and Fluid-Solid-Interaction Method to Rotor-Bearing System

2009 ◽  
Author(s):  
Huiping Liu ◽  
Hua Xu ◽  
Peter Ellison ◽  
Zhongmin Jin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Phase Change ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Rotational Velocity ◽  
Vertical Direction ◽  
Rotor Bearing ◽  
Fluid Solid Interaction ◽  
Bearing System

A powerful computational approach was developed for a complex rotor-bearing system to analyze the elasto-hydrodynamic lubrication (EHL) using computational fluid dynamics (CFD) and fluid solid interaction (FSI) techniques. To investigate the interaction of the dynamics and elastic deformation of the shaft and the lubrication of the journal bearing, a pure fluid bearing model and a rotor-bearing FSI model were created. The shaft was modelled as rigid and elastic respectively. Three different boundary conditions: Sommerfeld, Gu¨mbel and cavitation, were employed and compared in this study. The cavitation boundary was implemented based on the phase change caused by the pressure change between a liquid phase and a vapor phase. The load applied on the model was in the vertical direction, with a rotational velocity, representative of real working conditions of an experiment of a marine journal bearing. The results for the hydrodynamic case were compared with an in-house lubrication code based on Reynolds equation and the Reynolds boundary condition, and showed that the phase change method was adequate to deal with the cavitation problem of a rotor-bearing system. FSI was shown to be a powerful tool for the investigation of the hydrodynamic and elasto-hydrodynamic lubrication of a rotor-bearing system.

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