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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 24, Issue 6 - Dec 2008
Volume 24, Issue 5 - Oct 2008
Volume 24, Issue 4 - Aug 2008
Volume 24, Issue 3 - Jun 2008
Volume 24, Issue 2 - Apr 2008
Volume 24, Issue 1 - Feb 2008
Selecting the target year
A Study on Effects of the Changes in Lower Combustion Pressures and Pressure-Viscosity Index on Pin-Boss Bearing Lubrication of a Diesel Engine Piston Receiving High Combustion Pressure
Chun, Sang-Myung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 55~62
In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. In this paper, it will be investigated the tendency of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress. Finally, the pressure distributions on the oil film of piston pin bearings will be found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. Specially, it is investigated how the changes in combustion pressure at exhaust and intake stroke and the pressure-viscosity index effect on the film pressure distribution.
A Study on Tribological Characteristics of Materials for MEMS/NEMS Using Chemically Modified AFM tip
Heo, Jung-Chul ; Kim, Kwang-Seop ; Kim, Kyung-Woong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 63~71
Friction and adhesion tests were conducted to investigate tribological characteristics of materials for MEMS/NEMS using atomic force microscope (AFM). AFM Si tips were chemically modified with a self-assembled monolayer (SAM) derived from trichlorosilane like octadecyltrichlorosilane (OTS) and (1H, 1H, 2H, 2H-perfluorooctyl) trichlorosilane (FOTS), and various materials, such as Si, Al, Au, Cu, Ti and PMMA films, were prepared for the tests. SAMs were coated on Si wafer by dipping method prior to AFM tip to determine a proper dipping time. The proper dipping time was determined from the measurements of contact angle, surface energy and thickness of the SAMs. AFM tips were then coated with SAMs by using the same coating condition. Friction and adhesion forces between the AFM Si tip modified with SAM and MEMS/NEMS materials were measured. These forces were compared to those when AFM tip was uncoated. According to the results, after coating OTS and FOTS, the friction and adhesion forces on all materials used in the tests decreased; however, the effect of SAM on the reduction of friction and adhesion forces could be changed according to counterpart materials. OTS was the most effective to reduce the friction and adhesion forces when counterpart material was Cu film. In case of FOTS, friction and adhesion forces decreased the most effectively on Au films.
Tribological Performace of Architectural Fabrics
Choi, Won-Sik ; Lee, Ihn ; Park, Kang-Geun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 72~76
There are 5 kinds of architectural fabrics in our country recently. The test piece were made by attaching on the steel disk which has been tested of various range of the test conditions in pin-on-disk wear testing machine. The results show that the friction coefficient and wear rate of the architectural fabrics are heavily dependent on the load and materials. PVDF type was better than others in wear rate and friction coefficient.
Study on Scratch Characteristics of HDD Media and ZnO Thin Films by Ramp Loading Scratch Method
Kim, Dae-Eun ; Lee, Jung-Eun ; Lin, LiYu ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 77~81
In this work, ramp loading scratch method was used to evaluate the scratch characteristics of HDD media and ZnO thin films. Commercially available HDD media and ZnO thin films grown on silicon(100) substrate by sol-gel method were used. As for the ZnO films, the effects of annealing temperature after the film deposition process were also investigated. A custom built scratch tester was used to scratch the specimen under a ramp loading condition. The scratch track formed by ramp loading was measured by optical microscope and Atomic Force Microscopy (AFM). The wear depth and width were used to assess the scratch characteristics of the HDD Media and ZnO thin films. The results showed that ZnO film annealed at
had the best scratch resistance property. Also, the HDD media showed overall better scratch resistance than the ZnO films.
The Prototype Development of an Engine Oil Deterioration Sensor Installed Inside an Oil Filter
Chun, Sang-Myung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 82~89
The purpose of this study is to develop the proto type sensor installed inside an oil filter in order to detect oil deterioration level. The sensor is made up with two concentric cylinders with constant gap in between and a filter element inside the central area. The size will be designed as similar as real oil filters. The sensor will be tested on a test rig, which is circulating engine oil, with the same size of an oil filter adapting housing as real engines'. It will be measured the capacitance of a sample engine oil, then be able to be gotten the dielectric constant. The changes in the dielectric constant could be correlated with the engine oil deterioration level if the sensor development would be completed. In this paper, it will be shown the test results carrying out under variable temperature conditions at atmosphere pressure.
3-Dimensional Elastic-Plastic Contact Analysis Considering Subsurface Plastic Strain in a Half-Space
Cho, Yong-Joo ; Moon, Kil-Hwan ; Lee, Sang-Don ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 90~95
An elastic-plastic contact analysis is developed using a semi-analytical method. The elastic contact is solved within a Hertz theorem. The reciprocal theorem with initial strains is then introduced, to express the surface geometry as a function of contact stress and plastic strains. The irreversible nature of plasticity leads to an incremental formulation of the elastic-plastic contact problem, and an algorithm to solve this problem is set up. Closed form expression, which give residual stresses and surface displacements from plastic strains, are obtained by integration of the reciprocal theorem. The distribution of contact stress, residual stress and plastic strain are obtained by the changed surface geometry.
A Study of Sliding Friction and Wear Properties for PTFE Layer coated on Steel
Lee, Han-Young ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 2, 2008, Pages 96~103
PTFE is generally utilized as the form of composites with adding various fillers. The purpose of this paper lies on clarifying the friction and wear properties of the PTFE coating layer on steel. Especially, the effects of PTFE powder size for coating and surface roughness of the counter material on the properties are investigated. Sliding friction and wear tests are conducted at several sliding speeds by employing two types of PTFE coating layer using different powder sizes. One type of coating layer is composed of uniform fine powder, whereas the other type is made up of mixture powder of different sizes. As results, it is found that PTFE coating layer are effective to improve the wear resistance and to reduce the friction coefficient. It is clear that PTFE coating layers are abrasively removed by asperities of the counter material during sliding contact. However, PTFE coating layer with uniform fine powder shows somewhat better wear resistance than that with mixture powder of different sizes in low sliding speed region. It can be seen that the wear of the coating layer are drastically reduced because wear fragment from counter material are transferred to the coating layer. On the other hand, friction coefficient is shown not to be directly related with PTFE powder size in coating layer.