• Title/Summary/Keyword: thin plate thickness

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두께변화가 있는 복합재 평판의 램파 전파특성 (The characteristics of Lamb waves in a composite plate with thickness variation)

  • 한정호;김천곤
    • Composites Research
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    • 제18권2호
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    • pp.46-51
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    • 2005
  • 본 논문은 램파(Lamb waves)를 이용한 능동검사시스템을 구조 건전성 모니터링 시스템에 적용하기 위하여 램파의 특성연구를 수행하였다 연구는 보다 실제 구조물에 근접한 구조물을 고려하여 두께변화가 있는 준등방성 복합재 평판을 대상으로 PZT 탐촉자(transducer)를 표면에 부착하여 수행하였다. 본 연구에서는 두께변화로 인한 램파의 전파특성을 분석하기 위하여 간단하지만 새로운 기법을 적용하였다 본 연구의 결과는 램파의 전파특성은 상대적으로 얇은 구조물에 민감하였고 두께변화가 램파의 전파에 미치는 영향을 보여 주었다. 또한 본 연구에 사용한 분석기법은 램파를 이용한 구조 건전성 모니터링에 적용할 수 있는 가능성을 보여주었다.

긴 관통자에 의한 유한박판 및 적층표적재의 관통현상 연구 (On the Penetration Phenomena for Thin and Multi-Layered Finite Thickness Plates by a Long Rod Penetrator)

  • 이창현;홍성인
    • 대한기계학회논문집
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    • 제18권7호
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    • pp.1759-1772
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    • 1994
  • In this study, we re-examined the Tate's modified Bernoulli equation to study penetration phenomena for long rod projectile into single or multi-layered finite thickness plates. We used the force equlibrium equation at mushroomed nose/target interface instead of conventional pressure equation at the stagnation point. In our penetration model, we considered the velocity dependent $R_t$ value for semi-infinite target and considered only the back face effect for finite target. To compensate for $R_t$ value according to target's thickness and back face effect, we used the spherical cavity expansion theory for semi-infinite plate and used the cylindrical cavity expansion theory for finite plate. Also we developed the experimental technique using make screen to measure the penetration duration time at each layered plate. In 3-layered laminated RHA/mild steel/ A1 7039 plate, we observed that spall had occured around the back face of A1 7039 plate by the stress wave interaction. Through the comparison between theoretical and experimental data including Lambert's results, we conform that our study has good confidences.

A comprehensive analysis of horizontally polarized shear waves in a thin microstructural plate

  • Vikas Sharma;Satish Kumar
    • Structural Engineering and Mechanics
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    • 제85권4호
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    • pp.501-510
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    • 2023
  • Horizontally polarized shear waves (SH) have numerous applications in various scientific, engineering, and medical fields. The study deals with an investigation of SH-waves in a thin microstructural plate. The plate has been mathematically modelled by employing size dependent consistent couple stress theory, which involves a length parameter, known as characteristic length. Characteristic length is assumed to be of the order of internal microstructures of the material. Dispersion relations have been calculated for the propagation of SH-waves using different set of boundary conditions. Group velocity of the SH-waves has been calculated by using an analytical approach. The mathematical results obtained in the problem are discussed in detail and the impacts of characteristic length parameter and thickness of plate are presented on phase velocity of SH-waves through graphical illustrations.

사각형 박판의 비선형 열탄성 응력 수치해석 (Numerical Analysis of Nonlinear Thermoelastic Stress for Rectangular Thin Plate)

  • 김치경;김성중
    • 한국안전학회지
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    • 제19권4호
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    • pp.155-160
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    • 2004
  • 판의 두께에 선형적으로 변화하는 온도분포의 열하중을 받는 단순지지의 사각형 박판을 해석하였다. 열에 의한 판의 처짐이 판두께에 비해 상대적으로 과대하여 막응력이 부수적으로 발생하여 문제는 비선형 해석이 된다. 큰 처짐을 가지는 기하학적 비선형 문제를 지배하는 기본방정식은 von Karman 방정식이 사용되며 차분법으로 수치해석 한다. 차분화 하여 얻어지는 유사선형 대수방정식은 반복법을 도입하여 해석하고 결과치를 해석적으로 얻은 해와 비교 검토한다.

스크린 메쉬를 이용한 판형 히트 파이프의 개발 (Development of Flat Plate Heat Pipe Using Screen Meshes)

  • 이용덕;홍영호;김현태;김구영
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1506-1511
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    • 2003
  • The present study proposes a new structure for a flat plate heat pipe which could embody a thin thickness, any shapes and high heat density a unit area. It is on the structure for the formation of vapor passages and the support of the case of the flat plate heat pipe. A screen mesh is used as the one. To verify the validity of the one, the flat plate heat pipe of 1.08mm thickness was made with a layer of the screen mesh with 14 and 100 mesh number respectively and tested. Here the screen mesh with 14 mesh number plays a role of the vapor passage and the support of the case and the screen mesh with 100 mesh number functions as the wick structure. T he results show that the screen mesh excellently carries out the function of the vapor passage and the support of the case.

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맞대기 용접시의 각변형 거동에 관한 연구 (Behavior of angular distortion in butt joint welding of thin plate structure)

  • 배강열;김희진
    • Journal of Welding and Joining
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    • 제6권3호
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    • pp.21-26
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    • 1988
  • The behavior of angular distortion in butt joint wleding of thin plate structure is investigated with an experimental model and partially with a computational model. The experimental model studying the effects of specimene size and degree of restraint on the angular distorion offers a good method for analyzing the behavior of the distrotion. In addition, the distrotion during welding was demonstrated by both experimental measurement and numericla prediciton. The facts evealed in this study are as follows : 1) distrotion angles were changed with variations of specimene wldth. 2) With the restraint, angular distrotion was reduced to 20% to that of free joint. 3) After the restraint being removed, the effect of restraint was also remained. 4) Same heat input per unit thickness caused same amount of distortion. 5) The mode of angular distortion was expected to be changed with expected to be changed with time, i.e. convex movement during heating and concave one during cooling.

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Measurement and Effective Deburring for the Micro Burrs in Piercing Operation

  • Ko, Sung-Lim
    • International Journal of Precision Engineering and Manufacturing
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    • 제1권1호
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    • pp.152-159
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    • 2000
  • In piercing operation for small hole in very thin plate, micro burrs are formed. The micro burr is very difficult to remove because the thin plate is to be deformed during deburring and deteriorate accuracy. As a first step to remove the micro burrs effectively, the burr must be measured accurately as much as possible. For most micro burrs are so small as less than 10$\mu\textrm{m}$, it is very difficult to measure. Several methods are reviewed to measure the micro burr formed in piercing operation from very thin plate with thickness less than 0.1mm. Also the effective deburring methods are reviewed. Barreling ultrasonic and chemical deburring methods are performed and the results are compared.

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그림자효과를 이용하여 증착한 타이타늄 박막의 미세구조 및 형상 (Microstructure and Morphology of Titanium Thin Films Deposited by Using Shadow Effect)

  • 한창석;진성윤;권혁구
    • 한국재료학회지
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    • 제29권11호
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    • pp.709-714
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    • 2019
  • In order to observe the microstructure and morphology of porous titanium -oxide thin film, deposition is performed under a higher Ar gas pressure than is used in the general titanium thin film production method. Black titanium thin film is deposited on stainless steel wire and Cu thin plate at a pressure of about 12 Pa, but lustrous thin film is deposited at lower pressure. The black titanium thin film has a larger apparent thickness than that of the glossy thin film. As a result of scanning electron microscope observation, it is seen that the black thin film has an extremely porous structure and consists of a separated column with periodic step differences on the sides. In this configuration, due to the shadowing effect, the nuclei formed on the substrate periodically grow to form a step. The surface area of the black thin film on the Cu thin plate changes with the bias potential. It has been found that the bias of the small negative is effective in increasing the surface area of the black titanium thin film. These results suggest that porous titanium-oxide thin film can be fabricated by applying the appropriate oxidation process to black titanium thin film composed of separated columns.

무소음무진동 보보강공법 개발에 관한 연구(1) (Development of Retrofit Method for Beam Using Steel Plate Reinforced by Fiber Sheet (1))

  • 김우재;최종문;박상태;정상진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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    • pp.781-784
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    • 2004
  • Method of Steel plate reinforced by fiber sheet is advantageous in the secure loading facility. For this method are a light weight and a high strength, the thickness of steel can be reduced Effects of composite system are depreciated when the thickness of steel is thin. This is the result of the difference of ductility ratio with steel plate. Steel plate reinforced by fiber sheets confirms the ability of transformation. This is the result of the property of steel materials Steel plate reinforced by fiber sheet didn't display an enough performance when theadhesives are epoxy rosin. This is the result of the slide of the surface of stee1. The adhesive ability is varied by the number and span of anchor bolts. There wasn't happening the separation between steel and epoxy. Thus the method used in combination with anchor and epoxy is best excellent. This is the result of the upward of accumulation effects Shearing force is in proportion to the number of bolts. But the ability of shearing force per one bolt is reducing. Thickness of steel plate reinforced by fiber sheet must be designed so that steel is endure before concrete is wreck.

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Ultra Thin Reflective Flexible Liquid Crystal Display

  • Liu, Kang-Hung;Kuo, Chia-Wei;Ku, Chun-Kang;Chang, Chih-Yuan;Liao, Chi-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1080-1082
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    • 2008
  • An ultra-thin reflective flexible LCD film has been demonstrated. The 30% thickness of the display can be reduced by applying a quarter-wave-plate film as upper substrate. A low temperature alignment material and special designed photo spacer were applied in this new display. The bending behavior was improved by reduced thickness.

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