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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
Journal Basic Information
Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 18, Issue 6 - Dec 2002
Volume 18, Issue 5 - Oct 2002
Volume 18, Issue 4 - Aug 2002
Volume 18, Issue 3 - Jun 2002
Volume 18, Issue 2 - Apr 2002
Volume 18, Issue 1 - Feb 2002
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Synthesis and Thermal Stability of Polyol Esters
Chung, Keun-Wo ; Baek, Jin-Wook ; Kim, Young-Wun ; Seo, In-Ok ; Han, Jeong-Sik ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 319~323
Polyol esters were synthesized by condensation reaction of polyols (PE and DiPE) and linear acids such as valeric acid, caproic acid, heptylic acid and caprylic acid. The structures of polyol esters were confirmed by gas chromatography. Hot tube test was used test was used to measure thermal stability of polyol esters and its thermal properties depended on the structure of acid moiety contained in polyol esters.
Micro Friction and Wear Characteristics of Organically Modified Hybrid Ceramic Materials Synthesized by A Sol-Gel Process
Han, Hung-Gu ; Kong, Ho-Sung ; Yoon, Eui-Sung ; Yang, Seung-Ho ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 324~332
In order to enhance the thermal stability of binder materials of bonded type solid lubricants, several metal-alkoxide based sol-gel materials such as methyltrimethoxysilane(MTMOS), titaniumisopropoxide
were chemically modified by epoxy-, acrylic- and fluoro-silane compounds, respectively. Friction and wear characteristics of these hybrid ceramic materials were tested with a micro tribo-tester, and evaluated with respect to both heat-curing temperature and the time. Test results generally showed that hybrid ceramic materials modified by epoxy-silane compounds had a low friction compared to others. And the higher het-curing temperature and the longer heat treatment time resulted in the higher friction and the lower wear. IR spectroscopic analyses revealed that these results were caused mainly by the increased metal oxide content in hybrid ceramics when the heat-curing temperature was over
A Study on the Characteristics of Sound Source of Hydrodynamic Journal Bearings
Rho, Byoung-Hoo ; Kim, Kyung-Woong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 333~338
Results of theoretical investigations on acoustical properties of hydrodynamic journal bearings are presented. Nonlinear analysis including rotor imbalance is performed for a rotor-bearing system in order to obtain acoustical properties of hydrodynamic journal bearings. Furthermore, a cavitation algorithm, implementing the Jakobsson-Floberg-Olsson boundary condition, is adopted to predict cavitation regions in a fluid film. Acoustical properties of hydrodynamic journal bearings are identified through frequency analysis of oil pressure fluctuation calculated from the nonlinear transient analysis. The results show that the acoustical frequency spectra of the fluid film are pure tone spectra, containing the frequency of the shaft rotation and its super-harmonics. The analysis also shows that super-harmonics are predominant at the neighborhood of the fluid film reformation and rupture regions.
Effect of Electric Current on Friction Characteristics of Machine Driving Elements
Jun, Sung-Jae ; Cho, Yon-Sang ; Park, Heung-Sik ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 339~344
Whenever moving surfaces of machine driving elements interact in air and lubricating oil, oxidization film on the surfaces are generated. It is effect to prevent friction and wear on contact area. Since the electronic current progress the oxidization of metal, if the electronic flow be regulated, the thickness of oxidization film can be regulated and friction characteristics can be improved. But the electronic current can deteriorate friction characteristics, so various characteristics must be investigated on transforming of electronic current. Therefor, using the Norton equation in this study, short current were transformed between frictional materials using ball on disk type tester. It was studied on effect of electronic current for friction characteristics.
Numerical Study on The Injection-Compression Molding Characteristic of High Viscosity Plastic Fluids
Park, Gyun-Myoung ; Kim, Chung-Kyun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 345~350
Recently, as the development of manufacturing technique on SMC(sheet molding compound), various numerical and experimental approaches to injection and compression molding have been investigated. Injection and compression molding, however, has so various cases with complicated boundary condition that it is difficult to analyze mold characteristics precisely. In addition, since a slight change in process variables can significantly change the resulting mold thickness, a proper design is important to compression molding process. Therefore, in this study, the effects of various parameters on compression molding process have been investigated using FEM(finite element method) to formulate the melt front advancement during the mold filling process. To verify the results of present analysis, they are compared with those of reference. The results show a strong effect of initial charge volume, injection time and pressure as a result of variations in the rectangular charge shape.
Detecting of Scuffing Failure Using Acoustic Emission
Cho, Yong-Joo ; Kim, Jae-Hwan ; Kim, Tae-Wan ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 351~356
The surfaces of machine components in sliding contact such as bearing, gears and pistons etc. frequently operate under the condition of mixed lubrication due to high load, high speed and slip. These machine components often undergo the inception of scuffing in practical application. The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. However, it is difficult to find a universal mechanism to explain all scuffing phenomena because there are so many factors affecting the onset of scuffing. In this study, scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Acoustic Emission(AE) signal has been widely utilized to monitor the interaction at the friction interface. Using AE signals we can get an indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surfaces in real time. The FFT(Fast Fourier Transform) analyses of the AE signal are sued to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented.
Experimental Study on the Characteristics of the Pad Fluttering in a Tilting Pad Journal Bearing
Yang, Seong-Heon ; Kim, Cha-Seil ; Ha, Hyun-Chen ; Yang, Seong-Heon ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 357~363
The vibration characteristics of the pad fluttering in a fluid film tilting pad journal bearing (4-pad LBP) have been investigated experimentally under the different values of oil supply flow rate, bearing load and shaft speed. The vibration characteristics of the pad fluttering are estimated by measuring the time signal of circumferential distribution of the film thickness and the cascade plot of the response of the relative displacement between the bearing and the shaft. It is shown that the vibration frequency of the pad fluttering has a sub-synchronous frequency and almost does not change by the increase of shaft speed. However the vibration amplitude is increased by the increase of shaft speed. From those experimental results, pad fluttering can be thought of as a self-excited vibration. The incipient pad fluttering velocity is increased by the increase of oil supply flow rate and by the decrease of bearing load. It is observed that the vibration amplitude of the pad fluttering can be decrease by the control of supply oil flow rate effectively. And also It is known that the outbreak of pad fluttering does not concern with the shaft vibration.
A Study on the Performances of Hydrodynamic Air Lubricated Thrust Bearings of Several Types
Kang, Ji-Hoon ; Kim, Kyung-Woong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 18, issue 5, 2002, Pages 364~370
In this paper, numerical analyses were undertaken to calculate the static and dynamic performances of step-pocket, inward pumping spiral grooved, outward pumping spiral grooved and herringbone grooved bearings. For each bearing, optimal values for various design parameters were obtained to maximize the load capacity and the stiffness and bearing performances were calculated. The optimized performances of these bearings were compared to conclude that the performance of step-pocket bearing is better than the other bearings.