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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Tribologists and Lubrication Engineers
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The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 25, Issue 6 - Dec 2009
Volume 25, Issue 5 - Oct 2009
Volume 25, Issue 4 - Aug 2009
Volume 25, Issue 3 - Jun 2009
Volume 25, Issue 2 - Apr 2009
Volume 25, Issue 1 - Feb 2009
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Study of the Film Thickness Behaviors in the Elastohydrodynamic Lubrication of Circular Contact under the Dynamic Loading Condition with Multigrid Multilevel Method
Cho, Jae-Cheol ; Jang, Si-Youl ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 367~373
Many research of elastohydrodynamic lubrication (EHL) has been performed under the condition of steady state loading. However, mechanical elements undergo severe high loads that are in the fluctuating modes of frequency and amplitude. Conventional numerical method for the circular contact of EHL study has the difficulty in making the film thickness and pressure of EHL converged in high loads of steady state as well as fluctuating loading conditions. In this work, multigrid multilevel method are used for the stable convergence of film pressure and thickness under the conditions of high as well as varying loads, and very stable solutions of film behaviors with elastic deformation are obtained. Several results of dynamic loading condition are shown and compared with those of steady state condition in the aspects of circular EHL film thickness and pressure.
Finite Element Analysis on the Stress and Displacement Characteristics of Oil Pipe
Kim, Chung-Kyun ; Cho, Seung-Hyun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 374~380
This paper presents the stress and displacement characteristics of oil pipe using the finite element analysis. Displacement in axial direction and von Mises stress of a pipe were analyzed with three design factors, which are the pipe thickness, the corrugation pitch and the corrugation height, under uniform oil pressure. The FE computed results are presented between a conventional round pipe and a rectangular pipe, which is manufactured in this study. The computed FE results show that maximum displacement in axial direction and von Mises stress of pipe are increased linearly as the oil pressure increases. Also, they are increased linearly as the corrugation pitch, corrugation height and pipe thickness increases. von Mises stress of a rectangular pipe at the edge increases sharply compared with that of a conventional round pipe. Therefore, the strength of rectangular pipe is superior to that of a conventional round pipe.
Braking Characteristics of Wet-type Multiple Disc Brakes on Friction Materials
Bae, Myung-Ho ; Cho, Yon-Sang ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 381~386
In general, a brake system of axle for heavy duty machine as a wheel excavator makes use of wettype multiple disk brakes. These disk bakes are very important parts of heavy duty machine because they are dvanced in durability and braking power, and can be designed compactly. Thus, we adesigned and made wettype multiple disk brakes of axle for the wheel excavator to be localization of these imported all. In this study, wet multiple disk brakes were made a comparative test with the 3 types materials of friction disk by the SAE No.2 dynamometer. The friction characteristics were measured and analyzed to decide a suitable material as wear depth of friction disk and dynamic and static friction coefficient on temperature of oil and applied pressure.
Rig Tester Development for the Performance Validation of a Piston Oil Cooling Gallery
Chun, Sang-Myung ; Lee, Jeong-Keun ; Joo, Dae-Heon ; Ryu, Kwan-Ho ; Ha, Dae-Hong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 387~398
The operation condition of recently designed pistons for high power and high speed diesel engine become more severe due to the increment of combustion pressure and temperature. So, in order to overcome high temperature, the application of the mono-metal cast aluminum alloy piston featuring an enclosed cast-in open cooling gallery has increased. In this research, it is developed a PCJ (piston cooling jet) rig tester, described the test procedure and validated the performance of sample piston cooling gallery design. Then the test rig will be used for developing the design technology of piston cooling gallery. The test rig is composed with oil reservoir and pumping system, oil jet system, piston fixing and moving system, collecting oil measuring system, and data measuring and recording system. It will be measured collecting efficiencies under conditions of a few piston positions, oil jet pressures and oil viscosities for a piston cooling gallery. Furthermore, the PCJ rig tester will be used for the optimum design of the oil cooling gallery which being applied to increase the cooling efficiency of pistons in diesel engines satisfying the EURO V emission regulation and the more.
Experiments and Prediction of Pitting Life in Spur Gears
Kim, Jong-Sung ; Ju, Jin-Wook ; Lee, Sang-Don ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 399~403
The objective of this paper is to predict pitting initiation by using a contact analysis and subsurface stress. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions. Subsurface stress field is obtained using rectangular patch solutions. It is used Mesoscopic multiaxial fatigue criterion to predict contact fatigue life. It is important to predict pitting initiation to enhance reliability of the mechanical elements. Pitting life prediction in the spur gears which are fundamental mechanical element is presented in this paper.
On the Relationship between Material Removal and Interfacial Properties at Particulate Abrasive Machining Process
Sung, In-Ha ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 404~408
In this paper, the relationship between the material removal rate and the interfacial mechanical properties at particle-surface contact situation, which can be seen in an abrasive machining process using micro/nano-sized particles, was discussed. Friction and stiffnesses were measured experimentally on an atomic force microscope (AFM) by using colloidal probes which have a silica colloid particle in place of tip to simulate a particle-flat surface contact in an abrasive machining process. From the experimental investigation and theoretical contact analysis, the interfacial contact properties such as lateral stiffness of contact, friction, the material removal rate were presented with respect to some of material surfaces and the relationship between the properties as well.
Experimental Study on the Friction Characteristics of Pin-Bush Bearing Metals for Diesel Engine
Kim, Chung-Kyun ; Kim, Kyung-Seob ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 409~413
This paper presents the hardness and friction characteristics of pb-free pin-bush bearing metal, which is manufactured by a centrifugal casting technology. A bronze metal with a high hardness and low friction properties is usually used for Diesel engine pin-bush bearing and high pressure cylinder. Pb-free metal for pin-bush bearings shows a little high hardness of 120 Hv compared with that of a conventional Pb bearing metal of 100~110 Hv. In general, the friction coefficient of pin-bush bearings is affected by a rotating speed and a load for various rubbing contact modes. But a contact load is more influential parameter when the contact rubbing mode transits from a mixed lubrication to a dry friction contact. The experimental result shows that the friction coefficient is more unstable at the dry contact mode compared with that of other two rubbing modes such as oil film contact and mixed friction conditions.
A Basic Study on Blade Coating Process of Piston Skirt by Applying the Technology of Screen Printing - Parametric Study
Chun, Sang-Myung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 414~420
In this study, using the general expressions predicting the pressure under a blade and the volume of coating fluid passing through the blade edge, it is predicted the change of the coating wet film thickness related with various parameters determining the characteristics of this blade coating process. Using the results of this research, it can be found the optimized coating wet film thickness taking into account the parameters related with various coating process on various metal surfaces will be able to be predicted.
A Study on Temperature Field and Contact Pressure in Ventilated Disc-Pad Brake by 3D Thermo-mechanical Coupling Model
Hwang, Pyung ; Seo, Hee-Chang ; Wu, Xuan ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 421~426
The brake system is important part of automobile safety system. The disc brake system is divided two parts: the rotating axisymmetrical disc and the stationary pads. During braking, the kinetic energy and potential energy of moving vehicle were converted into the thermal energy through frictional heat between the brake disc and the pads. The frictional heat, which is generated on the interface of the disc and pads, can cause high temperature during the braking process. The object of present work is to determine temperature and thermal stress, to compare to simulation results and experimental results in the disc by partial 3D model of ventilated disc brake with appropriate boundary conditions. In the simulation process, the mechanical loads were applied to the thermo-mechanical coupling analysis in order to simulate the process of heat produced by friction.
Optimum Crowning Quantity Calculations of the Tapered Roller Bearing which Considers Tilting
Bae, Jong-Yup ; Lee, Sang-Don ; Doh, Byoung-Kwon ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 427~431
When a bearing roller is in contact with race ways. excessive pressure peaks occur at the ends of the contact region. They are called edge loading. In this study, a method to determinate crowning quantity of the tapered roller bearing which considers tilting. This method is based on contact analysis.
A Study on Lubrication Characteristics of Automotive Engine Oil Merchandised in Domestic
Kim, Shin ; Kang, Hyung-Kyu ; Lim, Tae-Yoon ; Kwon, Jong-Soo ; Kim, Jai-Gueon ; Choi, Dae-Sung ; Kim, Dong-Kil ; Jung, Choong-Sub ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 25, issue 6, 2009, Pages 432~437
The effect of oxidation in SAE 5W30 engine oils on friction and wear characteristics was investigated using reciprocating bench tester and shell 4-ball tester. Commercial engine oils were collected and oxidized using the KS M 2021 method modifying the oxidation time. Kinematic viscosity, total acid number(TAN), FT-IR spectrum and total base number(TBN) also measured to examine the chemical change of oils with oxidation. The results showed that TAN was slightly changed and Kinematic viscosity was suddenly increased during the oxidation stage. however, TBN results keep a constant slope after TBN linearly decreased with oxidation time. Spectroscopy results showed that spectrums were orderly increased at
during the oxidation time. Friction test results showed that oxidation of oils formed unstable friction layers causing higher fluctuating friction. however, the wear resistance was independent of oxidized time due to the different friction characteristics by oxidation. We found several factors in relation to lubrication properties with oxidation time. This factors were Viscosity, TBN, change of FT-IR spectrum, friction coefficient using reciprocating bench tester and wear scar.