• Title/Summary/Keyword: contact pressure distribution

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The study on the influence of contact pressure distribution on brake squeal analysis (브레이크 스퀼 해석에서 접촉압력분포의 영향에 관한 연구)

  • Lee, Ho-Gun;Son, Min-Hyuk;Seo, Young-Uk;Boo, Kwang-Seok;Kim, Heung-Seob
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1120-1124
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    • 2007
  • Recently in the automotive brake industry brake squeal noise has become one of the top automotive quality warranty issues. The contact pressure is used to predict friction coupling in the brake squeal analysis. The formulation of friction coupling has performed by nonlinear static analysis prior to the complex eigenvalue analysis. This paper proposes a validation methodology of squeal analysis using modal testing and contact analysis and examines the effect of predicted contact pressure that leads to the discrepancy between unstable complex mode and squeal frequency. This studies compose a three step validation process : examining the modal characteristics of component and assembly loaded contact pressure using modal testing and FEM analysis and verifying the contact pressure distribution using nonlinear static analysis and experiment. Finally, the unstable modes from complex eigenvalue analysis and realistic squeal frequency from the noise dynamometer are investigated.

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Finite Element Analysis of Fuel Cell Stack with Orthotropic Material Model (직교이방성 연료전지 스택의 유한요소 해석)

  • 전지훈;황운봉;조규택;김수환;임태원
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.175-178
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    • 2003
  • Mechanical behavior of a fuel stack was studied by the orthotropic material model. The fuel stack is mainly composed of bipolar plate (BP), gasket, end plate, membrane electrolyte assembly (MEA), and gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is very important to maintain a suitable contact pressure of BP, because it affects the efficiency of the fuel cell. This study compared mechanical behavior of various fastening types of the fuel cell stack. Bar, band, and modified band fastening type are used. The band fastening type showed that it reduces total volume of the cell, but it does not improve the contact pressure distribution of each BP. The modified band fastening type was designed by considering the deformations of band fastening type, and it showed a good enhancement of contact pressure distribution.

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A study on Contact Pressure Measurement of SM45C/STS410 Materials by Means of Ultrasonic Waves (초음파에 의한 SM45C/STS410재의 접촉압력측정에 관한 연구)

  • Yi, W.;Yun, I.S.;Jeong, E.S.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.11
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    • pp.92-99
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    • 1996
  • The contact pressure in jointed plates was measured by means of an improved ultrasonic technique. In order to get calibration curve, the relationship between contact pressure and ratio of boundary and bottom echo of normal beam probes were obtained for the calibration blocks with various surface roughness. The ratio of boundary and bottom echoes were measured for the upper/under plates locally compressed with uniform pressure, and the distribution of contact pressure was obtaines. The measured pressure has a good agreement with results of FEM analysis. Thus the proposed ultrasonic method in this work is very useful to measure the contact pressure.

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Analysis of the Contact Pressure Distribution and Kinetics of Knee Implant Using the Simulator (Simulator를 이용한 인공무릎관절 접촉면의 압력분포 및 운동성 분석)

  • 이문규;김종민;김동민;최귀원
    • Journal of Biomedical Engineering Research
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    • v.24 no.4
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    • pp.363-367
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    • 2003
  • Contact area and pressure are important factors which directly influence a life of knee implants. Since implant's mechanical functions should be experimentally evaluated for clinical use, many studies using a knee simulator and a pressure sensor system have been conducted. However it has not been reported that the contact pressure's distribution of a knee implant motion was estimated in real-time during a gate cycle. Therefore. the objective of this study was to analyze the contact pressure distribution for the motion of a joint using the knee simulator and I-scan sensor system. For this purpose, we developed a force-controlled dynamic knee simulator to evaluate the mechanical performance of artificial knee joint. This simulator includes a function of a soft tissue and has a 4-degree-of-freedom to represent an axial compressive load and a flexion angle. As axial compressive force and a flexion angle of the femoral component can be controlled by PC program. The pressure is also measured from I-scan system and simulator to visualize the pressure distribution on the joint contact surfaces under loading condition during walking cycle. The compressive loading curve was the major cause for the contact pressure distribution and its center move in a cycle as to a flexion angie. In conclusion, this system can be used to evaluate to the geometric interaction of femoral and tibial design due to a measured mechanical function such as a contact pressure, contact area and a motion of a loading center.

접촉결합부를 갖는 원통구조물의 열적,동적 특성 연구

  • 김선민;이선규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.244-249
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    • 1997
  • Internal and external heat sources will cause to deform to machine elements in the contact joint of structure,which results in the change of contact pressure distribution different from initial assembly. Heat induced variations of contact pressure will change the static and dynamic properties such as contact stiffness,damping as well as contact heat conduction in the structure. In order to design and control the intelligent machine tool operating in variant conditions more sophisticatedly, the good prediction for the changes of prescribed propeties are strongly required especially in the contact elements adjacent to the rotational or linear bearing This paper presents some computational and experimental results in regard to static and dynamic characteristics of the press-fitted bush and shaft assembly which is a model of the bearing innerrace and shaft assembly. In the condition of heat generation on the outer surface of the bush,the effects of changes in the negative clearance and the heat flux on pressure distribution and dynamic properties are investigated. Results of this study show that the edge effect of the bush and the initial clearance have effects on the transient dynamic characteristics significantiy.

Thermally-induced Mechanical Behavior of the Press-fitted Cylindrical Structure (죄임새 결합된 원통구조물의 열전도에 의한 기계적 특성변화)

  • 김선민;이선규
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.7
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    • pp.139-148
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    • 1998
  • Internal and external heat sources will cause to deform to machine elements in the contact joint of structure, which results in the change of contact pressure distribution different from initial assembly. Heat induced variations of contact pressure will change the static and dynamic properties such as contact stiffness, damping as well as contact heat conduction in the structure In order to design and control the intelligent machine tool operating in variant conditions more sophisticatedly, the good prediction for the changes of prescribed properties are strongly required especially in the contact elements adjacent to the rotational or linear bearing. This paper presents some computational and experimental results in regard to static and dynamic characteristics of the press-fitted bush and shaft assembly which is a model of the bearing innerrace and shaft assembly. In the condition of heat generation on the outer surface of the bush, the effects of changes in the negative clearance and the heat flux on pressure distribution and dynamic properties are investigated. Results of this study show that the edge effect of the bush and the initial clearance have effects on the transient dynamic characteristics significantly.

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Thermal Stress Analysis of a Fuel Cell Stack using an Orthotropic Material Model (복합재료 연료전지 스택의 열응력 해석)

  • Jeon Ji Hoon;Hwang Woonbong;Um Sukkee;Kim Soowhan;Lim Tae Won
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.206-209
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    • 2004
  • Mechanical behavior of a fuel stack was studied using an orthotropic material model. The fuel stack is essentially composed of a bipolar plate (BP), a gasket, an end plate, a membrane electrolyte assembly (MEA), and a gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is important to maintain a suitable contact pressure distribution of BP, because it influences the power efficiency of the fuel cell stack. When it is exposed to high temperature, its behavior must be stable. Hence, we performed stress analysis at high temperature as well as at room temperature. At high temperature, the contact pressure distribution becomes poor. Many patents have shown that using an elastomer can overcome this phenomena. Its effect was also studied. By using an elastomer, we found a good contact pressure distribution at high temperature as well as at room temperature.

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Effect of Stem Design on Contact Pressure and Stress Distribution of End-of-stem in Revision TKR (슬관절 재전치환술용 경골 삽입물 형상이 주대 말단부의 접촉압력과 응력 분포에 미치는 영향)

  • Kim, Yoon-Hyuk;Kwon, Oh-Soo;Park, Si-Mon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.11 s.188
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    • pp.126-134
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    • 2006
  • In this study, the effect of stem-end design on contact pressure and stress distribution in revision TKR was investigated using finite element method. The finite element model of tibia, including the cortical bone, the cancellous bone and canal, was developed based on CT images. The implant models with various stem lengths, diameters, friction coefficients, and press-fit effects were considered. The results showed that the longer stem length, the stronger press-fit, the bigger stem diameter, and the higher friction coefficient increased both peak contact pressure and Von-Mises stress distributions. The results supported the clinical hypothesis that peak contact pressure and stress are related to the stem end pain. The results of this study will be useful to design the stem and reduce the end-of-stem pain in revision TKR.

The Study on the Influence of Pad Wear on Brake Squeal Analysis (브레이크 스퀼 해석에서 패드 마모의 영향에 관한 연구)

  • Lee, Ho-Gun;Son, Min-Hyuk;Seo, Young-Wook;Boo, Kwang-Seok;Kim, Heung-Seob
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.11
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    • pp.930-936
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    • 2008
  • This paper studies the effect of pad at initial stage and wear during braking on the dynamic contact pressure distribution. Wear is influenced by variable factor (contact pressure, sliding speed, radius, temperature) during dynamic braking and variation in contact pressure distribution. Many researchers have conducted complex eigenvalue analysis considering wear characteristic with Lim and Ashby wear map. The conventional analysis method is assumed the pad has smooth and flat surfaces. The purpose of this paper is to validate that wear rate induced by braking is considered for the precise squeal prediction. After obtaining pad wear from experiment, it is incorporated with FE model of brake system. Finally, the comparisons in fugitive nature of squeal will be carried out between the complex eigenvalue analysis and noise dynamometer experiment.