• 제목/요약/키워드: sliding contact

검색결과 483건 처리시간 0.028초

인공 고관절 골두용 세라믹 복합재료에 대한 세라믹-세라믹 접촉 마멸 특성 분석 (Ceramic-Ceramic Wear of Zirconia/Alumina Composites for the Application of Total Hip Replacement)

  • 이권용;김환;김대준;이명현;서원선
    • Tribology and Lubricants
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    • 제21권5호
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    • pp.216-220
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    • 2005
  • The sliding wear behaviors of three different compositions of novel low temperature degradation-free zirconia/alumina (LTD-free Z/A) composites were examined in a ceramic-ceramic contact pair. The wear tests were performed by using a pin-on-disk type wear tester in a linear reciprocal sliding motion with a line contact in both dry and bovine serum lubricated conditions at room temperature. From the results of dry sliding wear tests, Z/A#1((5.3Y, 4.6Nb)-TZP/80 $vol\%Al_2O_3$) showed the best wear resistance among three kinds of LTD-free Z/A composites. For the bovine serum lubricated sliding wear tests, wear was too little to be measured for all kinds of Z/A composites. These novel LTD-free Z/A composites having excellent wear resistance demonstrated a potential as the alternative materials for the ceramic-ceramic contact pairs of femoral head and acetabular liner in total hip replacement.

수중 및 공기 중에서의 지르칼로이-4 튜브마멸 비교분석 (Comparison and Analysis of Zircaloy-4 Tube Wear in Air and Water Environment)

  • 김형규;박순종;강흥석;윤경호;송기남
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2001년도 제34회 추계학술대회 개최
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    • pp.19-26
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    • 2001
  • The wear characteristic of Zircaloy-4 tube, which is used for a cladding of light water reactor fuel rod, is investigated experimentally. The experiment is conducted with contacting the crossed tube specimens in air as well as in water at room temperature with various combination of contact normal force and sliding distance of reciprocating motion. The contour and the volume of each wear are examined to study the effect of contact condition and environment on wear. As a result, it is found that the wear volume in the water environment is larger than that in the air for all the contact (i.e., force and sliding distance) conditions. However, the wear depth is greater in air than in water if the contact normal force and the sliding distance are larger. These are explained by the ease of detachment of wear particles from the contact surface. On the other hand, workrate model is applied with the contact shear force range measured by our wear tester. Investigated is the correlation between the workrate and the wear volume increase rate of the present experiment. The parabolic curve is found to fit well for the present wear data.

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Finite motion analysis for multifingered robotic hand considering sliding effects

  • Chong, Nak-Young;Choi, Donghoon;Suh, Il-Hong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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    • pp.370-375
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    • 1992
  • An algorithm for the notion planning of the robotic hand is proposed to generate finite displacements and changes in orientation of objects by considering sliding effects between the fingertips and the object at contact points. Specifically, an optimization problem is firstly solved to find minimum contact forces and minimum joint velocities to impart a desired motion to the object at each time step. Then the instantaneous relative velocity at the contact point is found by determining velocities of the fingertip and the velocity of the object at the contact point. Finally time derivatives of the surface variables and contact angle of the fingertip and the object at the present time step is computed using the Montana's contact equation to find the contact parameters of the fingertip and the object at the next time step. To show the validity of the proposed algorithm, a numerical example is illustrated by employing the robotic hand manipulating a sphere with three fingers each of which has four joints.

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5절 평면형 메커니즘의 동적 포복에 관한 연구 (Study on Dynamic Crawling of The Five-bar Planar Mechanism)

  • 이정헌;임남식;김희국;이병주
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1045-1049
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    • 2005
  • In this paper, the dynamic crawling of a five-bar planar mechanism is investigated. One complete cycle of the crawling selected in this study consists of four different steps, i) sliding at one contact point between the mechanism and the ground, ii) changing its configuration without sliding at two contact points, iii) sliding at the other contact point, and iv) again changing its configuration without sliding at two contact points. In this type of crawling, the crawling mechanism maintains the shape of the parallel structure throughout a complete crawling cycle. The modeling algorithm for serial manipulators proposed by M. Thomas and et al.[1] is employed by introducing imaginary joints and links which represent the contact interfaces between the one end of the mechanism and the ground, while the other end of the mechanism is regarded as an end-effector of the imaginary serial manipulator which treats the reaction force and torque at the contact point as external forces. Then, a complete cycle of dynamic crawling of the mechanism is investigated through various computer simulations. The simulation result show that the stable crawling characteristics of the mechanism could be secured when the proper configurations depending on specified frictional constraints are met.

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후방압출에서 펀치형상에 따른 접촉경계면의 표면부하상태 (Surface Stress Profiles at the Contact Boundary in Backward Extrusion Processes for Various Punch Shapes)

  • 노정훈;김민태;비스아라;황병복
    • 소성∙가공
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    • 제18권7호
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    • pp.565-571
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    • 2009
  • This paper is concerned with the analysis on the surface stress profiles of perfectly plastic material in backward extrusion process. Due to heavy surface expansion appeared usually in the backward extrusion process, the tribological conditions along the interface between the material and the punch land are very severe. In the present study, the analyses have focused to reveal the surface conditions at the contact boundary for various punch shapes in terms of surface expansion, contact pressure, and relative movement between punch and workpiece which consists of sliding velocity and distance, respectively. Punch geometries adopted in the analysis include concave, hemispherical, pointed and ICFG recommended shapes. Extensive simulation has been conducted by applying the rigid-plastic finite element method to the backward extrusion process under different punch geometries. The simulation results are summarized in terms of surface expansion, contact pressure, sliding velocity and sliding distance at different reduction in height, deformation patterns, and load-stroke relationship, respectively.

Force-Reflecting Teleoperation for Grinding Work

  • Choo, Jung-Hoon;Lee, Jae-Yong;Lee, Jae-Won
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.824-828
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    • 2003
  • This paper explains problems of force-reflecting teleoperation grinding work and proposes some methods to solve those. For stable contact between robot tool(grindstone) and contact surface the mechanical impedance force control is used. The sliding phenomenon of grindstone has been appeared at the contact surface during the grinding work. The sliding problems caused by friction and rotation of grindstone are eliminated by using tangential direction sliding compensation control. The rotation force of grindstone makes the tool move to tangential direction along the surface suddenly even though an operator pushes the tool only in normal direction to the surface. Normal direction force control is applied for grinder not to roll and fracture on the grinding surface. Vibration problem of grindstone is decreased by second order low-pass filter. Therefore we can precise grinding work at the grinding surface and feel the reality

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미끄럼조건에 따라 TiN 코팅볼과 스틸디스크에 형성되는 산화막이 마찰특성에 미치는 영향 (The Effect of Oxide Layer Formed on TiN Coated Ball and Steel Disk on Friction Characteristics in Various Sliding Conditions)

  • 조정우;이영제
    • Tribology and Lubricants
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    • 제17권6호
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    • pp.459-466
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    • 2001
  • In this study, the effects of oxide layer formed on the contact parts of TiN coated ball and steel disk on friction characteristics in various sliding conditions were investigated. AISI52100 steel ball was used for the substrate of coated ball specimens, which were prepared by depositing TiN coating with 1(m in coating thickness. AISI1045 steel was used for the disk type counter-body. To investigate the effect of oxide layer on the contact parts of two materials, the tests were performed both in air for forming oxide layer on the contact parts and in nitrogen environment to avoid oxidation. From the test results, the frictional characteristic between the two materials was predominated by iron oxide layer that formed on wear tract of counter-body and this layer caused friction transition and high friction. And the adhesive wear occurred from steel disk to TiN coated ball caused the formation of oxide layer on counter parts between the two materials.

경계요소법을 이용한 미끄럼 접촉을 받고 있는 코팅층의 응력분포에 관한 연구 (A Study on Stress Distribution Using Boundary Element Analysis Due to Surface Coating in Sliding Contact)

  • 이강용;강진우
    • 대한기계학회논문집A
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    • 제25권2호
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    • pp.304-311
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    • 2001
  • The present work examines the influence of surface coating on the temperature and the thermo-mechanical stress field produced by friction due to sliding contact. A two-dimensional transient model of a layered medium submitted to a moving heat flux is prsented. A solution technique based on the boundary element method employing the multiregion technique is utilized. Results are presented showing the influence of coating thickness, thermal properties, Peclet number, and mechanical properties. It has been shown that the mechanical properties and thickness of coating have a significant influence on the stress field, even for low temperature increase. The effects of the ratios of shear modulus become more important for low temperature increase than the effects of the ratios of other mechanical properties.

경사선로에서의 차륜과 레일간 상호작용에 따른 마모 현상 연구 (The research on wear simulation between wheel and rail at inclined of Korea High Speed Railway)

  • 문태선;서보필;최정흠;한동철
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2003년도 학술대회지
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    • pp.112-117
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    • 2003
  • The purpose of this work is to general approach to numerically simulating wear in rolling and sliding contact area between wheel and rail interface based on the analysis of dynamics with general MBS package. A simulation scheme is developed that calculates the wear at a detailed level. The estimation of material removal follows Archard's wear equation which states that the reduction of volume is linearly proportional to the sliding distance, the normal applied load and the wear coefficient and inverse proportional to hardness. The main research application is the wheel-rail contact of Korea High Speed Railway.

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알루미나 세라믹스 순도에 따른 수윤활기구에 관한 연구 (Effect of Purity of Alumina Ceramics on the Water Lubrication Mechanism)

  • 진동규;박흥식;전태옥
    • Tribology and Lubricants
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    • 제11권4호
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    • pp.13-20
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    • 1995
  • The present study was undertaken to investigate the purity variation of the alumina ceramics on the water lubrication mechanism. The annular surface of wear testing specimens of the alumina ceramics with different alumina purity against STB2 was rubbed in the distilled water under various sliding speed, contact pressure and sliding distance. The friction coefficient decreased lowered with formation of corrosion products due to the tribochemical reation as the sliding speed and contact load was increased. With increased sliding speed, the lower purity of 85 percent contribute largely to even degree of the friction surface, even it have about $\mu$ of 0.3 degree by the influence of a pore and impurities SiO$_{2}$. The friction surface of ceramics protacted by oxide was transfer from STB2.