• Title/Summary/Keyword: 미끄럼 속도

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A Tribological Study of SiC-Steel Couples (탄화규소-강 미끄럼에서의 마모특성)

  • 장복기;김윤주
    • Journal of the Korean Ceramic Society
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    • v.34 no.1
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    • pp.7-12
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    • 1997
  • The wear behavior of SiC in SiC-steel sliding couple was investigated under various wear test conditions, such as solid state sliding - dry and wet air atmosphere - or lubricated sliding, sliding velocity and at-mosphere temperature. The effect of SiC fabrication process on the SiC wear rate was also studied under varying sliding velocities. Humidity of air plays a lubricating role in the solid state sliding, while the wear behavior is largely influenced by the sliding velocity, especially if the atmosphere is extremely dry. The fa-brication process of SiC and the surface roughness result in different wear rate depending on the magnitude of sliding velocity. High temperature is, among others, the most deteriorating factor of wear, thus being strongly wear-accelerating even under boundary lubrication.

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Some Effects of Sliding Velocity on The Elastohydrodynamic Squeeze Films (탄성 경계상 압착막에 대한 미끄럼 속도의 영향)

  • 유형선;이병철
    • Tribology and Lubricants
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    • v.2 no.1
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    • pp.46-52
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    • 1986
  • 얇은 유막위의 타이어 변형해석이나, 압착막댐퍼 설계등의 해석에 응용되는 변동 하중하의 탄성 경계상 유체 압착막의 해석을 Newton-Raphson 반복법을 사용하여 하였다. 유막두께의 계산은 등계수 요소를 사용하여 정확한 계산을 하였고 슬라이더의 궤적은 강쇄진동의 응답곡선과 유사함을 알 수 있었다. 특히 본 연구에서는 미끄럼 속도의 영향을 고려하였으며 유체가 베어링내에 생긴 포켓에 정체하고 있어서 미끄럼의 영향은 속도가 클때를 제외하고는 큰 영향을 미치지 못함을 알 수 있었다.

Numerical Analysis of the Slip Velocity and Temperature-Jump in Microchannel Using Langmuir Slip Boundary Condition (미소채널내의 Langmuir 미끄럼 경계조건을 통한 미끄럼 속도 및 급격한 온도변화에 관한 수치해석)

  • Kim, Sang-Woo;Kim, Hyun-Goo;Lee, Do-Hyung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.3
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    • pp.164-169
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    • 2009
  • The slip velocity and the temperature jumps for low-speed flow in microchannels are investigated using Langmuir slip boundary condition. This slip boundary condition is suggested to simulate micro flow. The current study analyzes Langmuir slip boundary condition theoretically and it analyzed numerically micro-Couette flow, micro-Poiseuille flow and grooved microchannel flow. First, to prove validity for Langmuir slip condition, an analytical solution for micro-Couette flow is derived from Navier-Stokes equations with Langmuir slip conditions and is compared with DSMC and an analytical solution with Maxwell slip boundary condition. Second, the numerical analysis is performed for micro-Poiseuille flow and grooved microchannel flow. The slip velocity and temperature distribution are compared with results of DSMC or Maxwell slip condition and those are shown in good agreement.

Effect of sliding velocity on the wear and friction characteristics of a carbon fiber composites (탄소 섬유 복합재의 마찰 및 마모 특성에 미치는 속도 효과)

  • Koh, Sung-Wi;Yang, Byeong-Chun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.4
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    • pp.337-343
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    • 2004
  • This paper presents an experimental study of friction and wear properties of a unidirectional oriented continuous crbon-fiber reinforced epoxy composite at the ambient temperature. Friction and wear experiments were conducted in the three principal sliding direction of the fiber orientation in the composite were selected against the stainless steel counterpart specularly processed were using a pin -on-disc apparatus. Friction coefficient and specific wear rate at various normal loads and sliding velocities wear determined. When sliding took place against smooth and hard counterpart, the hightest were resistance and the lowest friction coefficient were observed in the anti-parallel direction. The wear track of the worn specimens was examined with a scanning electron microscope(SEM) to observe the damaged fibers on the surface. In addition, SEM observations of the worn surfaces allowed to identify the involved different wear mechanisms.

Friction Characteristics of DLC and WC/C (DLC와 WC/C의 마찰특성)

  • Kim, Dong-Wook;Kim, Kyung-Woong
    • Tribology and Lubricants
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    • v.27 no.6
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    • pp.308-313
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    • 2011
  • In this study, friction tests were performed in order to investigate the effect of sliding velocity and normal load on the friction characteristics of DLC (a-C:H) and WC/C (a-C:H:W) using a ball-on-disk type friction tester. DLC and WC/C were deposited on AISI 52100 steel balls. Friction tests against carburized SCM 415 Cr-Mo steel disks were carried out under various sliding velocity (0.1, 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mm/s) and normal load (2.4, 4.8 and 9.6 N) conditions while the relative humidity was 20~40 % R.H. and air temperature was $16{\sim}24^{\circ}C$. As results, kinetic friction coefficients of DLC and WC/C were obtained under each test condition. The results show that the kinetic friction coefficients of DLC and WC/C generally increase with the increase in sliding velocity. And, under the same sliding velocity condition, the kinetic friction coefficients are almost constant regardless of normal load. In addition, the kinetic friction coefficients of DLC are lower than those of WC/C under the same test conditions.

A Study on the Friction Characteristics of Vulcanized Natural Rubber Plate (가황된 천연고무 판재의 마찰특성에 관한 연구)

  • Kim, D.J.;Nah, C.;Lee, Y.S.;Kim, W.D.
    • Elastomers and Composites
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    • v.36 no.2
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    • pp.121-129
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    • 2001
  • The friction characteristics of natural rubber plates under various conditions including sliding speed, normal force, hardness, lubrication conditions and thickness of plate are analyzed experimentally. The frictional force and normal force are measured by a tester pin and a load ceil with strain gages. Experimental results suggest that the coefficient of friction decreases with increasing the hardness of rubber and decreasing the thickness of plate. The effect of sliding speed is not significant over the speed range employed. The coefficient of friction is found to be about 0.1 under oil lubrication condition and varies from 0.9 to 3.9 under no lubrication condition.

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Wear Behavior of Al/SiC Composites Fabricated by Thermal Spray Process (1) - Effect of Sliding Speed on Wear Behavior - (용사법에 의해 제조된 Al/SiC 복합재료의 마모거동 (1) - 미끄럼 속도의 영향 -)

  • Lee, Kwang-Jin;Kim, Kyun-Tak;Kim, Yeong-Sik
    • Tribology and Lubricants
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    • v.27 no.6
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    • pp.351-355
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    • 2011
  • Al/SiC composites were fabricated by thermal spray process, and the dry sliding wear tests were performed using the various sliding speed of 10, 30, 60 and 90 RPM through 1000 cycles. The applied load was 10 N and radius of wear track was 15 mm. Wear tracks on the Al/SiC composites were investigated using scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). In the case of sliding speed of 10 RPM, adhesive wear behavior caused by plastic deformation of composits surface was observed. In the cases of sliding speed of 30, 60, 90 RPM, abrasive wear behavior on the adhered layer formed by debris were observed. Through this study, it was found that the wear behavior of Al/SiC composites was mainly influenced by the sliding speed.

A Study on the Tribological Characteristics of Purity $Al_2O_3-ZrO_2$ Ceramics materials ($Al_2O_3-ZrO_2$ 세라믹 재료의 순도에 따른 트라이볼로지 특성 연구)

  • Oh, Seong-Mo
    • Proceedings of the KAIS Fall Conference
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    • 2006.11a
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    • pp.76-79
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    • 2006
  • 세라믹 재료에 대한 트라이볼로지 특성은 기계장치의 실 링, 펌프부품, 미터 계 부품 등에 이용할 때 매우 중요하다. 본 연구에서는 각기 순도가 다른 알루미나와 지르코니아를 기계적 및 트라이볼로지적 특성에 미치는 영향을 고찰 하였다. 실험은 미끄럼거리와 미끄럼 속도, 그리고 마모량과 마찰계수 등을 서로 다른 순도에 따라 측정한 결과 알루미나의 순도 99.7%가 마찰계수와 마모 저항성이 매우 좋은 특성을 얻었으나, 지르코니아의 순도 95%는 상대적으로 마모량이 가장 크게 나타났다.

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Estimation of the Absolute Vehicle Speed using the Fifth Wheel (제 5바퀴속도와 비교한 차량절대속도 추정 알고리즘)

  • 황진권;송철기
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.3
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    • pp.58-65
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    • 2003
  • Vehicle acceleration data from an accelerometer and wheel speed data from standard, 50-tooth antilock braking system wheel speed sensors are used to estimate the absolute longitudinal speed of a vehicle. We develop the four velocity estimation algorithms. And we compare experimental results with the Butterworth filtered speed from the fifth wheel and find that it is possible to estimate absolute longitudinal vehicle speed during a hard braking maneuver lasting three seconds.