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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 20, Issue 6 - Dec 2004
Volume 20, Issue 5 - Oct 2004
Volume 20, Issue 4 - Aug 2004
Volume 20, Issue 3 - Jun 2004
Volume 20, Issue 2 - Apr 2004
Volume 20, Issue 1 - Feb 2004
Selecting the target year
Study of the Friction Force Measurements According to the Rolling-Sliding Ratios under the Condition of Elastohydrodynamic Lubrication
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 225~230
Most studies of elsatohydrodynamic lubrication are oriented only to the measurement of film thickness itself with optical interferometer. In order to exactly investigate the tribological characteristics of a certain lubricant, it is also important to get the information of traction behaviors as well. In this work, we developed a device for measuring the friction force of ehl contact condition as well as the film thickness. To verify the validity of the measuring system, the friction forces and film thicknesses under ehl condition are simultaneously measured with the variations of additive ratios of viscosity index improvers which cause non-linear tendencies of film thickness to contact velocity.
Shape Design Optimization of Disk Seal in
Gas Safety Valve
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 231~236
Sulfur Hexafluoride, S
is widely used for leak detection and as a gaseous dielectric in transformers, condensers and circuit breakers. S
gas is also effective as a cleanser in the semiconductor industry. This paper presents a numerical study of the sealing force of disk type seal in S
gas safety valve. The sealing force on the disk seal is analyzed by the FEM method based on the Taguch's experimental design technique. Disk seals in S
gas safety valve are designed with 9 design models based on 3 different contact length, compressive ratio and gas pressure. The calculated results of Cauchy stress and strain showed that the sealing characteristics of Teflon
PTFE is more effective compared to that of FKM(Viton), which is related to the stiffness of the materials. And also, the contact length of the disk seal is important design parameter for sealing the S
gas leakage in the safety valve.afety valve.
Micro/Nano Adhesion and Friction Characteristics of PTFE Coating Film Deposited by IBAD Method
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 237~244
Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.
The Static and Dynamic Performance Analyses of Air Foil Journal Bearing for Various Bump Foil Stiffness
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 245~251
This paper presents the effects of the bump foil stiffness on the static and dynamic performance of the foil journal bearings. Reynolds equation is used for the static and dynamic performance analyses. To consider the deflection of top foil the top foil is modeled as a elastic beam and the bump foil is modeled as a spring. So in the static performance analysis the load capacity is compared to the various bump foil stiffness and in the dynamic performance analysis the trajectory of journal center is compared to the various bump foil stiffness.
A Study on Fatigue Life under Elliptical Contact using High Cycle Fatigue Models
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 252~258
In this study, using high cycle fatigue (HCF) criteria, the simulation of rolling contact fatigue is conducted under elliptical contact. The HCF criteria fall into three categories: the critical plane approach, the stress invariant approach and the approach based on the mesoscopic scale. The accurate calculation of contact stresses and subsurface stresses is essential to the prediction of crack initiation life. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions and the subsurface stress field is obtained using rectangular patch solutions. The simulation results show that the critical load is decreasing rapidly and the site of crack initiation also moves rapidly to the surface from the subsurface when the friction coefficient exceeds a specific value for all of three fatigue criteria.
Design Optimization and Numerical Study of O-ring using Taguchi Method
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 259~265
The sealing performance of O-rings is affected by working conditions such as applied pressure, operation temperature, pre-compressed ratio and material properties. In this paper, a pressurized and compressed elastomeric bi-polymer O-ring in which is inserted into a rectangular groove is analyzed by non-linear MARC finite element program based on the Taguchi experimental method. O-rings with 9 different profile models are analyzed for design parameters that are related to the diameter ratio between outer diameter and inner one of bi-polymer O-ring, compressive ratio, groove angle and groove depth. The calculated FEM results showed that the affection ratio of design parameter dlD, which may control sealing pressure of O-rings, is the most influential parameter among the groove angle, groove depth and compression ratio.
Experimental Study on Micro-Scale Surface Texturing for Friction Reduction
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 266~271
The aim of this paper is to investigate the effect of surface texturing on reduction friction and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.
A Study on the Friction and Wear Characteristics of C-N Coated Spur Gear
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 272~277
This study deals with the friction and wear characteristics of C-N coated spur gear. The PSII apparatus was built and a SCM415 test piece and test gear with steel substrate was treated with carbon nitrogen by this apparatus. The composition and structure of the surface layer were analyzed and compared with that of PVD coated TiN layer. It was found that both of friction coefficient of C-N coating and TiN coating decreased with increasing load, however, C-N coating showed relatively lower friction coefficient than that of TiN coating. We was investigated the effect of C-N coating on hardness, friction and wear. The TiN coated gear showed a more serious friction phenomena than that of C-N coated gear. It was considered that coating of TiN, which was conducted at a vacuum chamber at about 500
, results in a tempering of base material that causes microstructural change, which in turn resulted in decreasing of hardness. The C-N coated gear and pinion had higher wear resistance that of TiN coated gear and pinion. C-N coating significantly improved the friction and wear resistance of the gear.
On the Sealing Force of Perfluoroelastomer O-rings Including Temperature Effects
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 278~283
O-ring seal is widely used for sealing pressure vessels and oil containers in various applications of mechanical equipments. The doughnut shape of the O-ring is very important components in most of the system assembly of mechanical apparatus. This paper presents the sealing force of a pressurized perfluoroelastomer O-ring, which is very important contact seal in sealing the semiconductor equipment. The sealing pressure is measured by experimental method and analyzed numerically by using the non-linear MARC finite element program. The seal tester is made to measure the contact force and displacement of the O-ring with an automatic control system of the working temperature. The results show the reasonable agreements between the computed FEM results and measured ones when the operating temperature is moderate temperature. But the compared values between the computed and tested results show a difference because of the increased temperature, which is related to the non-linear parameter of the O-ring material.
Average Flow Model with Elastic Deformation for CMP
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 20, issue 5, 2004, Pages 284~291
We present a three-dimensional average flow model considering elastic deformation of pad asperities for chemical mechanical planarization. To consider the contact deformation of pad asperities in the calculation of the flow factor, three-dimensional contact analysis of a semi-infinite solid based on the use of influence functions is conducted from computer generated three dimensional roughness data. The average Reynolds equation and the boundary condition of both force and momentum balance are used to investigate the effect of pad roughness and external pressure conditions on film thickness and wafer position angle.