• 제목/요약/키워드: contact pressure

검색결과 1,705건 처리시간 0.025초

거친 탄성 면접촉의 이론해석 (A Theoretical Analysis on The Elastic Rough Contact)

  • 유형선;이은상
    • Tribology and Lubricants
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    • 제2권2호
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    • pp.52-58
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    • 1986
  • The contact problem of a rigid smooth plane and computer-slmuiated elastic rough surfaces is studied by divided the sampling intervals into three groups. An iso-parametric element ,is used to calculate the contact pressure-separation relationship accurately. It is obtained that: 1) the more asperity shows the higher contact pressure, 2) the smaller element gives the better results but the effect is negligible.

Analysis of material dependency in an elastic - plastic contact models using contact mechanics approach

  • Gandhi, V.C. Sathish;Kumaravelan, R.;Ramesh, S.;Sriram, K.
    • Structural Engineering and Mechanics
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    • 제53권5호
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    • pp.1051-1066
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    • 2015
  • The study aims on the effect of material dependency in elastic- plastic contact models by contact analysis of sphere and flat contact model and wheel rail contact model by considering the material properties without friction. The various materials are selected for the analysis based on Young's modulus and yield strength ratio (E/Y). The simulation software 'ANSYS' is employed for this study. The sphere and flat contact model is considered as a flattening model, the stress and strain for different materials are estimated. The simulation of wheel-rail contact model is also performed and the results are compared with the flattening model. The comparative study has also been extended for finding out the mean contact pressure for different materials the E/Y values between 150 and 660. The results show that the elastic-plastic contact analysis for materials up to E/Y=296.6 is depend on the nature of material properties and also for this material the mean contact pressure to yield strength reaches 2.65.

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

  • 김선민;이선규
    • 한국정밀공학회지
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    • 제15권7호
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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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성인 편마비 환자의 편측 무시정도에 따른 족저압 비교 (The Comparison of Plantar Pressure Distribution regarding the Extent of Hemineglect in Adult Hemiplegia)

  • 차용준;김경
    • 대한물리의학회지
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    • 제5권1호
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    • pp.43-51
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    • 2010
  • Purpose : The purpose of this study was to compare plantar pressure distribution between affected side and unaffected side and to analyze plantar pressure distribution of affected side according to the extent of hemineglect in the adult hemiplegia. Methods : Twenty-five hemiplegia participated in this study. The analysis of plantar pressure distribution was conducted by the F-scan system, and the extent of hemineglect was evaluated with line-bisection test. While the subject walked about 10 meters in their comfortable speed the plantar pressure was evaluated and stored. Results : Total contact area, AP CoP trajectory, contact pressure of mid-foot of the affected side were significantly different from the unaffected side. Total contact area, AP CoP trajectory and contact pressure of mid-foot were smaller than those of unaffected side. In the comparison among the group according to the extent of hemineglect, AP CoP trajectory of subject who has severe hemineglect was significantly different from the patient that has no hemineglect and it was shorter than that of no hemineglect. Conclusion : The plantar pressure distribution was generally different between affected side and unaffected side and the hemineglect affected negatively the patient to move CoP forwardly while walking. Accordingly, it will help the clinician to understand the hemineglect which has an effect on abnormal walking and to intervent the hemiplegia who has a neglection to the affected side.

접촉면 형상에 따른 O-링의 접촉거동해석에 관한 연구 (On the Contact Behavior Analysis of the O-ring Depending on the Contact Surface Profiles)

  • 김청균
    • 대한기계학회논문집A
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    • 제29권2호
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    • pp.169-175
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    • 2005
  • In this paper, the contact stress and strain distributions in elastomer O-ring seals have been analyzed using a non-linear finite element method. The stress behavior of PTFE materials is assumed as Odgen model because the sealing clearance between the flange and the surface of the O-ring is not small and the sealing pressure of working fluids covers from the atmospheric pressure to high pressure of 15MPa. The contact normal force and stress in wavy O-rings in which is developed for this analysis are uniformly distributed along the flange and the wall of the rectangular groove. And the normal sealing forces are also kept high compared to other contact sealing models such as the conventional O-ring and X-ring, Thus, the FEM computed results indicate that the sealing characteristic of wavy O-rings is food compared with other contact seals.

Weiss형 등속조인트 볼 홈의 접촉응력평가 (Contact Stress Evaluations for the Ball Groove of Weiss Type Constant velocity joint)

  • 김완두;이순복
    • Tribology and Lubricants
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    • 제5권2호
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    • pp.60-67
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    • 1989
  • For the life prediction and fatigue failure prevention of the constant velocity joint, the maximum equivalent stress and its location in depth from the contact area are essential. These values give the fundamental information to determine the depth of the surface hardening treatment at the contact area. Contact stresses are evaluated at the surface and subsurface of the ball groove of the Weiss type constant velocity joint. The maximum contact pressure and the maximum equivalent stress are obtained. The effects of various parameters such as the radius of ball groove, friction coefficient, and residual stress are studied. The maximum equivalent stress and the maximum contact pressure increase as the radius of the ball grove increases. The location of the maximum equivalent stress moves toward surface as the friction coefficient increases. It was also found that the maximum equivalent stress becomes minimum when the compressire residual stress is about 0.16 times of the maximum contact pressure.

회외족의 Wedge Insole 각에 따른 보행 시 접지 시간, 접지면적 및 족저압력의 비교 (The Effect of the Wedge Insole Angle of Supinated Group on Foot Contact Time, Foot Contact Area and Foot Pressure)

  • 이효택;김용재
    • 수산해양교육연구
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    • 제22권4호
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    • pp.508-515
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    • 2010
  • This study was conducted on male college students with supinated foot to measure the foot pressure by having them wear three kinds of wedge insoles ($0^{\circ}$, $3.5^{\circ}$, $7^{\circ}$). Foot contact time, foot contact area, peak pressure and mean pressure were measured using a foot pressure distribution measuring instrument. And the surface of the foot sole was divided into 10 areas. Regarding foot contact time, there was no statistically significant difference by showing $0.69{\pm}0.004$ seconds at $3.5^{\circ}$ and $0.68{\pm}0.006$ seconds at $0^{\circ}$ and $7^{\circ}$. Regarding the foot contact area, it appeared broad in the inside area of the foot according to wedge insole, and there was statistically significant difference in the area 1 of the rear foot(p< .01) and the area 3 of the middle foot(p< .05). The peak pressure by foot area decreased in the outside of the foot according to wedge insole, while increasing in the inside of the foot. Among the areas, there was statistically significant in the area 2 of the rear foot (p< .01) and the area 3 of the middle foot (p< .05). Regarding the mean pressure by foot area, the pressure roughly increased in the inside area of the foot according to wedge insole, while decreasing in the outside of the foot.

최적 핵연료 접촉 열전도도 모델 개발을 위한 예비 연구 (Preliminary Study for the Development of Optimum Fuel Contact Conductance Model)

  • 양용식;신창환
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2488-2493
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    • 2007
  • A gap conductance is very important factor which can affect nuclear fuel temperature. Especially, in case of an annular fuel, a gap conductance effect can lead an unexpected heat split phenomena which is caused by a large difference of an inner and outer gap conductance. The gap conductance mechanism is very complicated behavior due to the its strong dependency on microscopic factors such as a contact surface roughness, local contact pressure and local temperature. In this paper, for the decision of test temperature and pressure range, a procedure and calculation results of in-reactor fuel temperature and pressure analysis are summarized which can be applied to test equipment design and determination of test matrix. Based upon analysis results, it is concluded that the minimum and maximum test temperature are $300^{\circ}C$ and $530^{\circ}C$ respectively, and the maximum pellet/cladding interfacial contact pressure should be observed up to 45MPa.

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Atomistic simulation and investigation of nanoindentation, contact pressure and nanohardness

  • Chen, Chuin-Shan;Wang, Chien-Kai;Chang, Shu-Wei
    • Interaction and multiscale mechanics
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    • 제1권4호
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    • pp.411-422
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    • 2008
  • Atomistic simulation of nanoindentation with spherical indenters was carried out to study dislocation structures, mean contact pressure, and nanohardness of Au and Al thin films. Slip vectors and atomic stresses were used to characterize the dislocation processes. Two different characteristics were found in the induced dislocation structures: wide-spread slip activities in Al, and confined and intact structures in Au. For both samples, the mean contact pressure varied significantly during the early stages of indentation but reached a steady value soon after the first apparent load drop. This indicates that the nanohardness of Al and Au is not affected by the indentation depth for spherical indenters, even at the atomistic scale.

Triboelectrification based Multifunctional Tactile Sensors

  • Park, Hyosik;Kim, Jeongeun;Lee, Ju-Hyuck
    • 센서학회지
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    • 제31권3호
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    • pp.139-144
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    • 2022
  • Advanced tactile sensors are receiving significant attention in various industries such as extended reality, electronic skin, organic user interfaces, and robotics. The capabilities of advanced tactile sensors require a variety of functions, including position sensing, pressure sensing, and material recognition. Moreover, they should comsume less power and be bio-friendly with human contact. Recently, a tactile sensor based on the triboelectrification effect was developed. Triboelectric tactile sensors have the advantages of wide material availability, simple structure, and low manufacturing cost. Because they generate electricity by contact, they have low power consumption compared to conventional tactile sensors such as capacitive and piezoresistive. Furthermore, they have the ability to recognize the contact material as well as execute position and pressure sensing functions using the triboelectrification effect. The aim of this study is to introduce the progress of research on triboelectrification-based tactile sensors with various functions such as position sensing, pressure sensing and contact material recognition.