• 제목/요약/키워드: contact pressure

검색결과 1,705건 처리시간 0.023초

Air-Bag Head 가압식 300mm 웨이퍼 폴리싱 테이블의 가압 분포 해석 (Analysis of Contact Pressure for a 300mm Wafer Polishing Table with Air-Bag Head)

  • 노승국
    • 한국생산제조학회지
    • /
    • 제22권2호
    • /
    • pp.310-317
    • /
    • 2013
  • In this paper, the contact pressure of the wafer and polishing pad for final polishing process for 300 mm-wafer were investigated through numerical analysis using FEM tool, ANSYS. The distribution of the contact pressure is one of main parameters which affects on the flatness and surface roughness of polished wafers. Two types of polishing head, a hard type head with ceramic disk and a soft type head with air bag were considered. The effects of the deformation and initial shape of table on the contact pressure were also examined. Both heads and tables were modeled as 3D finite element model from solid model, and the material properties of polishing pads and rubber plate for the air-bag head were obtained from tensile tests. The contact pressure deviation on wafer surface was smaller with air bag head than hard type head even when the table had form errors such as convex or concave. From this 3D analysis, it could be concluded that the air-bag head has better uniformity of the contact pressure on wafer. Also, the effects of inner diameter of air bag and radial clearance between wafer and retainer were investigated as view point of contact pressure concentration on the edge of wafer.

압입축의 파손 저감을 위한 설계 방법에 대한 연구 (Design Method to Reduce the Press-Fitted Assembly Dama)

  • 변성광;최하영;이동형
    • 한국기계가공학회지
    • /
    • 제20권5호
    • /
    • pp.128-134
    • /
    • 2021
  • A press-fitted shaft is an essential part used in industrial machines, and it is generally used to transmit large quantities of power. Very high contact pressure occurs at the end parts of the contact between the shaft and boss, which are press-fitted shaft components. Such contact pressure not only damages the contact surface of a press-fitted shaft but also reduces its fatigue strength. To improve a press-fitted shaft's fatigue strength, the contact pressure on the contact surface, which directly affects the fatigue strength, should be minimized. Thus, in this study, the design configuration optimization of the end part of the boss was based on the approximate optimization method and was aimed at minimizing the contact pressure at the end of a press-fitted shaft. Comparison of the contact pressure and the contact stress of a conventional press-fitted shaft with those of the optimized press-fitted shaft showed that the boss design of the optimized press-fitted shaft effectively improved the fatigue life.

임의의 누름압 분포를 나타내는 플랫형 블레이드 스프링 레일의 곡면 형상 (Study on the Profile of Body Spring in the Flat Type Wiper Blade for an Intended Contact Pressure Distribution)

  • 송경준;이형일
    • 한국자동차공학회논문집
    • /
    • 제21권2호
    • /
    • pp.55-62
    • /
    • 2013
  • An analytical procedure to determine a proper profile of the spring rail that generates intended contact pressure distribution in the flat wiper blade is introduced. The flat wiper blade is one piece blade and subjected to pressing force at a center point. In this type of blade, contact pressure distribution in the tip of rubber strip is determined by the pressing force, the initial profile of the blade before contact and bending stiffness of the blade. Experimentally obtained bending stiffness of the blade assembly is almost identical to that of the spring rail. Principle of reciprocity has been used to define the initial profile of spring rail from the deformed profile that is assumed to be identical to the windshield glass profile. The procedure has been verified experimentally by measuring the contact pressure of the blade assembled with the spring rail designed by the procedure proposed here. Measured contact pressure distributions of the blades show good agreements with intended distributions over the entire blade span. Consequently, it can be concluded that proposed procedure has relatively good accuracy in developing the spring rail for flat blade having a specific contact pressure distribution.

Patellofemoral contact mechanics after transposition of tibial tuberosity in dogs

  • Park, Donghee;Kang, Jinsu;Kim, Namsoo;Heo, Suyoung
    • Journal of Veterinary Science
    • /
    • 제21권4호
    • /
    • pp.67.1-67.11
    • /
    • 2020
  • Background: Tibial tuberosity transposition (TTT) causes caudalization of the patellar ligament insertion in canine medial patellar luxation, which can lead to increases in patellofemoral contact pressure. Objectives: The purpose of this study is to confirm the effect of patellofemoral contact mechanics after craniolateral and caudolateral transposition of tibial tuberosity in normal canine hindlimbs. Methods: Craniolateral and caudolateral transposition of tibial tuberosity was performed in 5 specimens, respectively. The pressure was measured in the specimen before TTT, and then in the same specimen after TTT. In this process, data was obtained in 10 specimens. The measurement results were output as visualization data through the manufacturer's software and numerical data through spreadsheet. Based on these 2 data and the anatomical structure of the patellofemoral joint (PFJ) surface, whole measurement area was analysed by dividing into medial, lateral and central area. Results: In craniolateralization of tibial tuberosity, total, medial, central contact pressure was decreased and lateral contact pressure was not statistically changed lateral contact pressure than normal PFJ. In caudolateralization of tibial tuberosity, total, lateral contact pressure was increased and medial contact pressure was not statistically changed than normal PFJ. Although not statistically significant changed, central contact pressure in caudolateralization of tibial tuberosity was increased in all 5 specimens. Conclusions: These results imply that traditional TTT, prone to caudal shift of patellar tendon, can increase retropatellar pressure may lead to various complications and diseases of the stifle joint.

Cu25Cr 접점재료의 성형압력에 따른 소결 및 전기적 특성에 관한 연구 (A study on the effects of compacting pressure on the electrical & sintering characteristics of Cu25Cr contact material)

  • 연영명;박홍태;오일성;이경행
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
    • /
    • pp.1065-1068
    • /
    • 2001
  • Effects of compacting pressure on the electrical and sintering characteristics of Cu25Cr contact material have been investigated. Cu25Cr contact materials were prepared by solid and liquid-phase sintering methods varying compacting pressure. Influence of compacting pressure on electrical characteristics were investigated in the cylindrical stainless-steel vessel using L-C resonant circuit. The physical and electrical properties of solid-phase sintered Cu25Cr material were found to be improved by increased compacting pressure. On the other hand, it was found that compacting pressure had little influence in case of liquid-phase sintered Cu25Cr material. After conditioning, contact resistance of Cu25Cr material was decreased regardless of compacting pressure. With increased compacting pressure, interrupting ability was shown to be increased.

  • PDF

15분간의 지속적인 스트레칭이 족저압과 족저면적 변화에 미치는 영향 (Acute Effects of Prolonged 15minnute Static Stretching on Foot Contact Area Surface and Foot Pressure Changed in Young Adults)

  • 국중석
    • 대한물리치료과학회지
    • /
    • 제18권4호
    • /
    • pp.59-64
    • /
    • 2011
  • Purpose : The purpose of this study was to evaluate the effects of the stretching of the calf muscles on foot pressure and contact area in young adult. Participants stood on a wedge board that was sloped between 15~25 degree for 15min. After stretching participants stood quietly on force plate, result was recorded. Participants stood on a force plate for 1 min in eye closed condition, and them the foot pressure and area was recorded. The following variables were calculated off-line: anterior and posterior foot pressure and contact area, medial and lateral foot pressure and contact area. Results showed that anterior pressure change due to stretch, but mediolateral was not significant. This result suggested that stretching of the calf muscle has the effect of increasing anterior pressure by flexibility change on calf muscle, so this effects might be effective intervention for reduce of serious problem to neurologic patients in therapy session.

  • PDF

축대칭 압출 공정에서 상계법을 이용한 금형 접족면압의 계산 (Calculation of Contact Pressure to the Die of Axisymmetric Extrusion by Using Upper Bound Solution)

  • 최영;여홍태;허관도
    • 한국정밀공학회지
    • /
    • 제21권12호
    • /
    • pp.133-139
    • /
    • 2004
  • In general, the contact pressure to the die cannot be easily determined by using upper bound solution. Recently, the authors have proposed the method determining the contact pressure with the upper bound solution for the forming with the plane stain plastic deformation. In this paper, the method is applied to an axisymmetric forward extrusion process. The contact pressure to the die of the axisymmetric extrusion has been determined with the upper bound solution and compared with the result of rigid plastic FEM. The optimal semi-angles of die have been obtained minimizing the relative contact pressure to die fur the extrusion ratio.

AZ31B 마그네슘 합금의 온간 마찰 특성 연구 (Study of Frictional Behavior of AZ31B Mg Alloy at Elevated Temperature)

  • 한수식
    • 소성∙가공
    • /
    • 제27권3호
    • /
    • pp.160-164
    • /
    • 2018
  • The success of warm forming of Mg alloy sheets is very dependent on its frictional behavior at elevated temperatures. The effects of contact pressure and sliding length on the frictional characteristics of AZ31B Mg alloy sheet were investigated at elevated temperature and at room temperature. The contact pressure range for the friction test was determined through FE analysis of the roof panel which is a candidate for Mg alloy application. According to the experimental results, the frictional behavior of the Mg alloy sheet is equally highly influenced by both sliding length and contact pressure at room temperature. At elevated temperatures, however, the sliding length has a more dominant influence on the frictional characteristics of the Mg alloy sheet than the contact pressure, if the contact pressure is lower than a certain level.

압축강도 평가를 위한 지능형 응력예측기 구축 (Construction of the Intelligence Stress Predictor for Compression Strength Evaluation)

  • 박원규;우영환;이종구;윤인식
    • 한국공작기계학회논문집
    • /
    • 제10권6호
    • /
    • pp.95-101
    • /
    • 2001
  • This work is concerned with construction of the intelligence stress predictor far compression strength evaluation using neural network-ultrasonic waves. The contact pressure in jointed plates was measured by using ultrasonic technique. Neural network is used to evaluate and predict contact pressure from the results of the calibration curves. The organized neural system was leaned with the accuracy of 99%, as a result of learning the ultrasonic echo ratio to the contact pressure measurement between SM45C and STS410 materials. And it could be evaluated and predicted with the accuracy of 90% in the evaluation of ultrasonic echo ratio difference in the same surface roughness and contact pressure, and 85% in the prediction of virtual ultrasonic echo ratio. Thus the proposed stress predictor is very useful for the evaluation and prediction of the contact pressure between SM45C and STS410 materials.

  • PDF

차륜 및 차축의 변형을 고려한 차륜-레일 접촉해석 (Wheel-Rail Contact Analysis considering the Deformation of Wheel and Axle)

  • 최하영;이동형;유원희;이종수
    • 한국정밀공학회지
    • /
    • 제27권8호
    • /
    • pp.20-27
    • /
    • 2010
  • A precise evaluation of the contact position and the distribution of contact pressure in a wheel-rail interface analysis is one of the most important procedures to predict fatigue life and wear of wheel and rail. This paper presents the analysis result of finite element method(FEM) to investigate how the deformation of a wheelset, which is the assembly of wheel and axle of a railroad vehicle, affect the contact analysis of wheel and rail. 3D-FEM was used to analyze three contact models; a model with only wheel, a model with wheelset, and a model with simplified wheel and rail geometry. The analysis result of the contact position and the distribution of contact pressure are discussed. It is shown that the analysis results of a model with wheelset represent largest value with respect to contact pressure and contact stress. Furthermore, it is found that the distribution of contact pressure and the contact position is highly affected by the deformation of wheel and axle. It is concluded that the deformation of axle should be considered to evaluate the exact contact parameters in a wheel-rail contact analysis.