Friction and Wear Characteristics of Bearing Materials Under Boundary Lubricated Conditions

1979 ◽  
Vol 101 (4) ◽  
pp. 474-480
Author(s):  
Yoshiki Doi ◽  
Tutom Haba
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Friction And Wear ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Load Parameter ◽  
Empirical Equations ◽  
Flash Temperature ◽  
Bearing Materials ◽  
Friction And Wear Characteristics

This paper presents the results of tests performed with journal bearings with seven bearing materials, at a variety of loads and rotational speeds. On the basis of these results some empirical equations for predicting the behavior of boundary lubricated journal bearings are proposed. It is demonstrated that a noncontact parameter, that is, the ratio of elastohydrodynamic film thickness to the combined roughness of the two mating surfaces, plays the same important role in the behavior of the boundary lubricated journal bearing as in rolling-sliding elements. The friction coefficient is represented by the noncontact parameter and a nondimensional load parameter, besides by material constants, unless preseizure occurs. A critical flash temperature can predict the preseizure. Moreover it is shown that the correlation between the specific wear and the friction coefficient is close at any operating condition.

Performance Analysis of a Nonrecessed Hybrid Conical Journal Bearing Compensated With Capillary Restrictors

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Prashant G. Khakse ◽  
Vikas M. Phalle ◽  
S. S. Mantha
Keyword(s):  
Performance Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Parameter ◽  
Radial Load ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Fluid Film Thickness ◽  
Film Stiffness

The present paper deals with the performance analysis of a nonrecessed hole-entry hydrostatic/hybrid conical journal bearing with capillary restrictors. Finite element method has been used for solving the modified Reynolds equation governing the flow of lubricant in the clearance space of journal and bearing. The hole-entry hybrid conical journal bearing performance characteristics have been depicted for a wide range of radial load parameter (W¯r  = 0.25–1.5) with uniform distribution of holes at an angle of 30 deg in the circumferential direction. The numerically simulated results have been presented in terms of maximum fluid film pressure, minimum fluid film thickness, lubricant flow rate, direct fluid film stiffness coefficients, direct fluid film damping coefficients, and stability threshold speed. However, the proposed investigation of nonrecess hole-entry hybrid conical journal bearing shows important performance for bearing stiffness and minimum fluid film thickness at variable radial load and at given operating speed.

scholarly journals Friction and Wear Monitoring Methods for Journal Bearings of Geared Turbofans Based on Acoustic Emission Signals and Machine Learning

Lubricants ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 29 ◽  
Author(s):  
Noushin Mokhtari ◽  
Jonathan Gerald Pelham ◽  
Sebastian Nowoisky ◽  
José-Luis Bote-Garcia ◽  
Clemens Gühmann
Keyword(s):  
Machine Learning ◽  
Acoustic Emission ◽  
Friction And Wear ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Wear Volume ◽  
Time Frequency ◽  
Ae Signal ◽  
Ae Signals

In this work, effective methods for monitoring friction and wear of journal bearings integrated in future UltraFan® jet engines containing a gearbox are presented. These methods are based on machine learning algorithms applied to Acoustic Emission (AE) signals. The three friction states: dry (boundary), mixed, and fluid friction of journal bearings are classified by pre-processing the AE signals with windowing and high-pass filtering, extracting separation effective features from time, frequency, and time-frequency domain using continuous wavelet transform (CWT) and a Support Vector Machine (SVM) as the classifier. Furthermore, it is shown that journal bearing friction classification is not only possible under variable rotational speed and load, but also under different oil viscosities generated by varying oil inlet temperatures. A method used to identify the location of occurring mixed friction events over the journal bearing circumference is shown in this paper. The time-based AE signal is fused with the phase shift information of an incremental encoder to achieve an AE signal based on the angle domain. The possibility of monitoring the run-in wear of journal bearings is investigated by using the extracted separation effective AE features. Validation was done by tactile roughness measurements of the surface. There is an obvious AE feature change visible with increasing run-in wear. Furthermore, these investigations show also the opportunity to determine the friction intensity. Long-term wear investigations were done by carrying out long-term wear tests under constant rotational speeds, loads, and oil inlet temperatures. Roughness and roundness measurements were done in order to calculate the wear volume for validation. The integrated AE Root Mean Square (RMS) shows a good correlation with the journal bearing wear volume.

Optimal Design of Modified Cylindrical Gear Based on Minimum Flash Temperature of Tooth Surfaces

2013 ◽  
Vol 655-657 ◽  
pp. 573-577
Author(s):  
Jin Ke Jiang ◽  
Zong De Fang ◽  
Xian Long Peng
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Contact Line ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Uniform Grid ◽  
Normal Vector ◽  
Flash Temperature ◽  
Oil Film ◽  
Tooth Surfaces

Considering the gap of the contact line of modified involute cylindrical gears influencing on loads, oil film thickness, the friction coefficient was determined on the basis theory of TCA、 LTCA and EHL. so oil film thickness and friction coefficient corresponded with loads on contact line were dispersed, which was used to computed discrete temperature according to the Blok flash temperature formula. and an approach of modified tooth surface optimum design based on the minimum flash temperature was proposed: the modified tooth surfaces was defined as a sum of theoretical tooth and cubic B-spline fit surface based on the uniform grid points created by double parabolas and a straight line and whose normal vector was deduced, besides, used genetic algorithm to optimize the parameter of curve, and get the best modified gear tooth surfaces. the results shows that oil film is thicker in engaging-out, coefficient of friction is contrary, which is responsible for lower flash temperature in engaging-in, besides the flash temperature has little changes in the single tooth meshing zone, and helical gear has a lower flash temperature than spur gear due to higher overlap ratio.

Combined Influence of Misalignment and Orifice Diameter on the Static Performances of Hydrostatic, Water-Lubricated Journal Bearings

2014 ◽  
Vol 607 ◽  
pp. 608-611
Author(s):  
Hui Hui Feng ◽  
Chun Dong Xu ◽  
Feng Feng Wang
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Power Loss ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Rigid Rotor ◽  
Static Performance

The water-lubricated bearings have gained an increasing focus to overcome the disadvantages of the oil film bearings and gas bearings. In this paper, the influences of orifice diameter in aligned and misaligned conditions on the static performance of two hydrostatic, four-recess, water-lubricated journal bearings used to support a rigid rotor, are investigated. The steady Reynolds equation for the journal bearing for the turbulent bulk flow and the film thickness expression considering tilting angles are used and numerically solved by finite difference method. Results demonstrate that the static performances, such as the quality, power loss and temperature rise are affected by the tilting angles, orifice diameter to some degree.

Numerical Investigation on the Mixed Lubrication Performance of Water-Lubricated Coupled Journal and Thrust Bearings

2019 ◽  
Author(s):  
Yanfeng Han ◽  
Guo Xiang ◽  
Jiaxu Wang
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Thrust Bearing ◽  
Journal Bearing ◽  
Load Capacity ◽  
Hydrodynamic Pressure ◽  
Mixed Lubrication ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Lubrication Performance

Abstract The mixed lubrication performance of water-lubricated coupled journal and thrust bearing (simplified as coupled bearing) is investigated by a developed numerical model. To ensure the continuity of hydrodynamic pressure and flow at the common boundary between the journal and thrust bearing, the conformal transformation is introduced to unify the solution domain of the Reynolds equation. In the presented study, the coupled effects between the journal and thrust bearing are discussed. The effects of the thrust bearing geometric film thickness on the mixed lubrication performance, including the load capacity, contact load and friction coefficient, of the journal bearing are investigated. And the effects of the journal bearing eccentricity ratio on the mixed lubrication performance of the thrust bearing are also investigated. The simulated results indicate the mutual effects between the journal and thrust bearing cannot be ignored in the coupled bearing system. The increasing thrust bearing geometric film thickness generates a decrease in load capacity of journal bearing. There exists an optimal eccentricity ratio of journal bearing that yields the minimum friction coefficient of the thrust bearing.

Tribological Relationship for Sintered Bearing Using Taguchi Technique

2015 ◽  
Vol 3 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Priya Shekhar Gajjal ◽  
Geeta Lathkar ◽  
Harijan Bagchi
Keyword(s):  
Regression Analysis ◽  
Process Parameters ◽  
Friction And Wear ◽  
Journal Bearing ◽  
Taguchi Technique ◽  
Bearing Material ◽  
Sintered Bearing ◽  
Bearing Materials ◽  
The Relationship ◽  
Manufacturing Parameters

Sintered bearing materials have been developed in order to be used as a journal bearing material without lubrication. This paper presents a study of influence of manufacturing and process parameters on friction and wear of bearing. Plan of experiments, based on Taguchi technique was used to acquire the data in a controlled way. An orthogonal array (L27) and analysis of variance were employed to investigate the influence of parameters of dry ferrous bearing. The objective is to establish a correlation between process and manufacturing parameters with friction and wear by multiple regression analysis. Finally, confirmation tests were performed to validate the relationship as suggested through experiments.

Friction and wear characteristics of ceramics composite under multidirectional motions

2021 ◽  
pp. 135065012110421
Author(s):  
Mohammad A Chowdhury ◽  
Bengir A Shuvho ◽  
Nayem Hossain ◽  
Mahamudul Hassan ◽  
Uttam K Debnath ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Surface Hardness ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Wear Characteristics ◽  
Disc Configuration ◽  
Friction And Wear Characteristics

The friction and wear characteristics of stainless steel diffused with Si-based ceramics were investigated using pin-and-disc configuration under reciprocation motion, rotational motion, and simultaneous motion. The pin material was diffused by the combination of 60% Ti2O3, 30% Al2O3, and 10% Si2O3. Experiments have been carried out both in diffused and non-diffused conditions. Both the friction coefficient and wear rate have been possible to reduce by diffused pin material. The effects of both friction coefficient and wear rate have been studied on ceramics composites at different pin-and-disc motions. Experiments were conducted underpin motions of 0.15–0.25 m/s, disc motions of 0.5–0.6 m/s, and normal loads of 2.5–3.5 N. A relation was found among friction, wear and surface hardness of the composite. The friction coefficient and wear resistance were improved of stainless steel diffused with ceramics. Scanning electron microscopic analysis was performed to observe the morphology of ceramic and pin material.

Friction and Wear Characteristics of Cu-Based P/M Brake Friction Materials with Addition of Fe and C

2014 ◽  
Vol 661 ◽  
pp. 21-26 ◽  
Author(s):  
Talib Ria Jaafar ◽  
Mohd Asri Selamat ◽  
Z.J. Rusila ◽  
M.F. Ismail
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Friction And Wear ◽  
Volume Loss ◽  
Friction Materials ◽  
Wear Characteristics ◽  
Weight Percentage ◽  
Two Samples ◽  
Friction And Wear Characteristics

Cu-based powder metallurgy friction materials were prepared by varying of Fe and C (% weight) in the friction components. The samples were compacted under the load of 24 metric tonnes and sintered at a temperature of 950 °C for 45 minutes. The friction and wear characteristics the materials developed were studied using Chase machine. The results show that Fe and C have different friction and wear characteristics. The friction coefficient of Cu-30%Fe-15%C sample maintained to be high and slightly increased after the drum temperature of 350°C and subsequently stable throughout tests. The friction of Cu-20%Fe-10%C stable until the drum temperature of 450°C and then its start to decay slightly until the end of the test. On the hand, the friction of Cu-10%Fe-5%C start to decay after sliding a few minutes at the drum temperature of 230°C. Thus, it could be postulated that the friction coefficient increased with increasing weight percentage of Fe and C in the friction components. However, the volume loss shows that there is no direct correlation with the Fe and C content. The volume loss of Cu-10%Fe-5%C was higher than the two samples which had the lowest hardness. On the hand, the volume loss of the Cu-30%Fe-15%C was slightly higher than Cu20%Fe-10%C as result of higher porosity and lower hardness. Wear mechanisms of abrasion, adhesion and thermal were observed to be operated during sliding process.

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