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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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Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 26, Issue 6 - Dec 2010
Volume 26, Issue 5 - Oct 2010
Volume 26, Issue 4 - Aug 2010
Volume 26, Issue 3 - Jun 2010
Volume 26, Issue 2 - Apr 2010
Volume 26, Issue 1 - Feb 2010
Selecting the target year
Lubrication Characteristics of Laser Textured Parallel Thrust Bearing : Part 2 - Effect of Dimple Location
Park, Tae-Jo ; Hwang, Yun-Geon ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 1~6
In the last decade, laser surface texturing (LST) has emerged as a viable option of surface engineering. Many problems related with mechanical components such as thrust bearings, mechanical face seals and piston rings, etc, LST result in significant improvement in load capacity, wear resistance and reduction in friction force. It is mainly experimentally reported the micro-dimpled bearing surfaces can reduce friction force, however, precise theoretical results are not presented until now. In this paper, a commercial computational fluid dynamics(CFD) code, FLUENT is used to investigate the lubrication characteristics of a parallel thrust bearing having 3-dimensional micro-dimple. The results show that the pressure, velocity and density distributions are highly affected by the location and number of dimple. The numerical method and results can be use in design of optimum dimple characteristics, and further researches are required.
Tribological Characteristics of Phosphorated Starch Based Electrorheological Fluid
Jang, Min-Gyu ; Lee, Chul-Hee ; Choi, Jea-Young ; Sohn, Jung-Woo ; Choi, Seung-Bok ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 7~13
This experimental study presents tribological characteristics under boundary lubrication contacts associated with electrorheolocal (ER) fluid. ER fluid is prepared by using phosphorated starch particles and silicone oil. Experimental apparatus of tribological tester is designed and constructed to evaluate tribological characteristics of pin specimens. Wear tests under boundary lubrication of ER fluid are experimentally performed under consideration of several operational factors such as normal load, sliding distance, sliding speed and specimen materials: steel, copper and aluminum. After wear test, microscopic surface changes of the worn pin specimens are analyzed in order to investigate measured wear characteristics by using the scanning electron microscope (SEM) as well as surface profilometer. In addition, the chemical wear characteristics are investigated by using energy dispersive x-ray spectroscopy (EDS). Moreover, friction coefficient measurements under different materials of pin specimens are conducted for the tribological investigations. In order to verify the effect of starch phosphate particles in ER fluid, the wear test results with ER fluid are compared with test results with only silicone oil. The results clearly present that the phosphorated starch based ER fluid shows the stabilized wear as well as friction characteristics after run-in operations, but the wear rate under ER fluid is increased.
Tribological Properties of Nanoporous Structured Alumina Film
Kim, Hyo-Sang ; Kim, Dae-Hyun ; Ahn, Hyo-Sok ; Hahn, Jun-Hee ; Woo, Lee ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 14~20
Tribological properties of nanoporous structured alumina film was investigated. Alumina film (AAO: anodic aluminum oxide) of
thickness having nanopores of 45 nm diameter with 105 nm interpore-diatance was fabricated by mild anodization process. Reciprocating ball-on-flat sliding friction tests using 1 mm diameter steel ball as a counterpart were carried out with wide range of normal load from 1 mN to 1 N in an ambient environment. The morphology of worn surfaces were analyzed using scanning electron microscopy. The friction coefficient was strongly influenced by the applied normal load. Smooth layer patches were formed on the worn surface of both AAO and steel ball at relatively high load (100 mN and 1 N) due to tribochemical reaction and compaction of wear debris. These tribolayers contributed to the lower friction at high loads. Extremely thin layer patches, due to mild plastic deformation of surface layer, were sparsely distributed on the worn surface of AAO at low loads (1 mN and 10 mN) without the evidence of tribochemical reaction. Delaminated wear particles were generated at high loads by fatigue due to repeated loading and sliding.
Performance Comparison of Collecting Efficiencies to Various Types of Piston Oil Cooling Gallery
Lee, Jeong-Keun ; Chun, Sang-Myung ; Joo, Dae-Heon ; Ryu, Kwan-Ho ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 21~30
In this research, it is investigated the collecting efficiency of jet oil to several types of piston oil cooling gallery by using recently developed PCJ (piston cooling jet) rig tester. So it will be selected for a better design of piston oil cooling gallery. The collecting efficiencies at each type of piston cooling galleries are measured under conditions of a few piston positions, and several oil jet pressures and oil viscosities. Furthermore, the type of jet cone will be compared for a few jet pressure conditions. The selected type of piston oil cooling gallery is planned to be applied to the target engine which is now developing to satisfy the EURO VI emission regulation.
Temperature Field and Thermal Stress Simulation of Solid Brake Disc Based on Three-dimensional Model
Hwang, Pyung ; Seo, Hee-Chang ; Wu, Xuan ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 31~36
The brake system is an important part of the automobile safety system. The disc brake system is divided into two parts: a rotating axi-symmetrical disc, and the stationary pads. The frictional heat, which is generated on the interface of the disc and pads, can cause high temperatures during the braking process. The frictional heat source (the pads) is moving on the disc and the location is time-dependent. Our study applies a moving heat source, which is defined by the time and space variable on the frictional surface, in order to simulate the frictional heat behavior accurately during the braking process. The object of the present work is the determination of the temperature distribution and thermal stress in the solid disc by non-axisymmetric 3D modeling for repeated braking.
Prediction of Rotordynamic Coefficients for High-Performance-Pump Seal Using CFD Analysis
Choe, Bok-Seong ; Ha, Tae-Woong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 37~43
Precise prediction of rotordynamic coefficients for annular type seal of turbomachinery is necessary for enhancing their vibrational stability and various prediction methods have been developed. As the seal passage is designed complicatedly, the analysis based on Bulk-flow concept which has been mainly used in predicting seal dynamics is limited. In order to improve the seal rotordynamic prediction, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved. In this study, 3D CFD(Computational Fluid Dynamics) analysis has been performed for predicting rotordynamic coefficients of non-contact type annular plain seal using FLUENT. Comparing with the results of Bulk-flow model analysis, the result of 3D CFD analysis shows good agreement.
Development of a Shear Testing Machine for a Miniature Single Solder Ball Joint using Piezoelectric Loading Device
Kwon, Yong-Sang ; Ko, Guk-Jong ; Kim, Ho-Gyeong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 44~51
A miniature shear testing machine was designed and developed, adopting a piezoelectric actuator with mechanical advantage using 4 levers in order to investigate shear behavior of a small solder ball. The final output displacement was initially expected to be 2.88 mm without load resistance, considering the lever ratio of 24 and the piezo displacement of 0.12 mm with an exciting voltage of 10 V. However, the final plunger displacement
can be expected as
as a function of piezoelectric force F due to the stiffness of various levers and connectors and piezo actuator. The shear behavior of lead-free solder ball in diameter of
was successfully investigated in a speed range of 2 mm/s~0.0035 mm/s using this designed device.
The Friction Characteristics of Roll Stand in the Cooling Slat Fin M/C
Choi, Won-Sik ; Lee, Sung-Yong ; Kwon, Ju-Ry ; Jin, Eun-Young ; Mun, Hee-Joon ; Lee, In ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 52~55
This study investigates the friction of the roll stands in the high performance multi- holes slate fin machine which pin is using in heat transfer of radiator, oil cooler, inter cooler, condenser and evaporator. The roll stand part is very important to maintain the high performance fin machine. This multi-holes form roll type is the first time in our country so it will be helpful to increases the export and product of heat transfer. It was include the technical of form rolling system which was self development. Then it will be improve the electric home appliances, future motor vehicle device and industrial machine.
A Study of Camber Effect on Contact Pressure Between Cam and Roller
Chon, Seo-Hyeon ; Lee, Sang-Don ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 56~60
Contact pressure occurs whenever two surfaces contact between cam and roller. Especially excessive pressure peaks occur at the ends of the contact region. Such as scuffing or pitting will be induced when these operating conditions continuously occur on the surface. Camber effect is given to reduce damage by changing the shape of roller. The objective of this paper is to calculate contact pressure distribution by using a contact analysis considering camber and tilting angle. These results predict that camber effect of all machine components have influence on contact pressure distribution.
Case Study of Tribological Failure Characteristics in Automotive Steering System
Kim, Chung-Kyun ; Lee, Il-Kwon ; Cho, Seung-Hyun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 61~67
The purpose of this paper is to study and analyze the failure examples on tribological characteristics of an automotive steering system. In this failure study, the grease leakage may stick leaked grease, dust, and wear particles between pinion and rack gears in mechanical steering system. In the case of seal failures such as a rod seal, o-ring and oil seals, the gear box and oil pump do not operate properly due to lack of oils. This means that oil pump does not supply a working fluid and produce a normal oil pressure of the steering system. This leads to leak a working fluid from the seals and produce a wear between pinion and rack gears. Especially, the leaked oil is usually mixed with internal wear particles and foreign dust/fine sands. Thus no leakage of working oils is very important design concepts, which is strongly related to the sealing components and smoothly operating of the mechanical friction parts of power steering system.
A Comparative Study on Tribological Characteristics between Ni-P Electroless Plating and TiAlN Coating on Anodized Aluminum Alloy
Lee, Gyu-Sun ; Bae, Sung-Hoon ; Lee, Young-Ze ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 68~72
A ceramic coating is a surface treatment method that is being used widely in the industrial field, recently. Ni-P plating is also being used widely because of its corrosion resistance and low cost. An anodizing method is applicable to aluminum alloy. An anodizing method generates a thick oxide layer on the surface and then, that heightens hardness and protects the surface. These surface treatments are applied to various mechanical components and treated surfaces relatively move one another. In this study, tribological characteristics of Ni-P plating and TiAlN coating on anodized Al alloy are compared. The counterpart, anodized Al alloy, is worn out abrasively by Ni-P plating and TiAlN coating that have higher hardness. Abrasively worn debris accumulated on the surfaces of Ni-P plating and TiAlN coating, and then transferred layer is formed. This transferred layer affects the amplitude of variation of friction coefficient, which is related to noise and vibration. The amplitude of variation of friction coefficient of Ni-P plating is lower than those of TiAlN coating during the tests.
Case Study on Integrated In-line Oil Monitoring Sensor for Machine Condition Monitoring of Steel Making Industry
Kong, H. ; Han, H.G. ; Kwak, J.S. ; Chang, W.S. ; Im, G.G. ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 73~77
One of the important trends for condition monitoring in the 21st century is the development of smart sensors that will permit the cost-effective continuous monitoring of key machine equipments. In this study, an integrated in-line oil monitoring sensor assigned for continuous in situ monitoring multiple parameters of oil performance is presented. The sensor estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical density of oil in three optical wave-bands ('Red', 'Green' and 'Blue') and water content is evaluated as relative saturation of oil by water. In order to evaluate the sensor's effectiveness, the sensor was applied to several used oil samples in steel making industry and the results were compared with those measured by standard test methods.
The Lubricity of Biodiesel as Alternative Fuel
Lim, Young-Kwan ; Lee, Cheon-Ho ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 26, issue 1, 2010, Pages 78~87
Biodiesel have been studied as alternative fuel due to solution of air pollution and fossil fuel exhaustion. Biodiesel from animal fat and vegetable oil was known as eco-friendly fuel like low toxicity, biodegradable compare to petrodiesel. In particular, biodiesel have excellent lubricity due to involved ester functional group. This paper shows the biodiesel's lubricity based on worldwide biodiesel research.