• Title/Summary/Keyword: 변형 측정

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Measurement of 3-D Deformation by Using Holospeckle Interferometry (홀로스펙클 간섭법을 이용한 3차원 변형측정 연구)

  • 박승옥;권영하;유성규
    • Korean Journal of Optics and Photonics
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    • v.1 no.1
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    • pp.12-15
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    • 1990
  • Holospeckle interferometry, the combined technique of holographic interferometry and speckle photography, was applied to the measurement of 3-D contact deformation created by an indentor. This new tech$.$ nique makes possible to measure both in-plane and out-of-plane displacements from one photographic plate. In this study, the optical system based on image holography was set up. In order to enhance the size and the contrast of the speckle, a proper magnification and a low reference beam ratio was used as compared with the conventional holographic interferometry technique. This system shows the magnified and clear holographic interference fringe as well as Young's fringe patterns.tterns.

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Displacement Prediction of Swept Composite Cantilevered Panel Wings Using Strains (변형률을 이용한 복합재 평판 후퇴익 구조물의 변위 예측)

  • Kim, Mun-Guk;You, Je-Gyun;Kim, So-Young;Kim, In-Gul;Kim, Geun-Sang;Jeon, Min-Hyeok
    • Composites Research
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    • v.30 no.5
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    • pp.280-287
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    • 2017
  • The complex deformation of the swept composite wing occurs due to the torsional load and bending load during the flight. Therefore, prediction for displacement of swept composite wing is required for structural health monitoring. Wing displacements can be predicted by using relationship between displacements and strains. The strain distributions on the fixed-end are complex due to the geometric shape of the swept wing. Because of those strain distribution, the wing displacement can be diversely predicted by the strain sensing locations. In this paper, displacements prediction of swept composite wing was performed by considering complex strain distributions. The predicted displacements under various loading condition were consistent with those calculated by FEA and verified through the bending test.

소성 불안정 이론 및 그 응용

  • 전기찬
    • Journal of the KSME
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    • v.29 no.3
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    • pp.244-252
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    • 1989
  • 평면변형조건에서 성형한계를 빠르고 정확하게 측정할 수 있는 방법을 개발하는 것도 중요하다. 평면변형조건에서의 성형한계를 구하는 데에는 펀치 스트레칭이 주로 이용되지만 그 외에도 여러 가지 방법들이 시도되고 있다. 평면변형조건에서 펀치스트레칭 시험을 행하여 파단이 일 어날 때까지의 펀치 행정거리를 한계 돔 높이(limiting dome height)라 하여 선진 제국에서는 박판금속의 성형성에 대한 품질관리 수단으로서 이용하고 있다. 우리나라의 박판금속의 성형 업계에서도 새로운 공정의 개발에 있어서 성형한계도와 변형측정법을 이용하므로서 시행착오를 줄이고, 한계돔 높이에 의한 품질관리기법을 이용하므로서 불량율저감 및 생산성 향상을 기할 필요가 있다 하겠다. 각종 재료에 대하여 측정한 성형한계에 관한 자료는 그 대표적인 값(예를 들면, 평면변형에서의 성형한계 값)으로서 컴퓨터에 저장하여두면 성형성에 대한 CAE에 의한 분석시에 편리하게 이용될 수 있다.

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Magnetostriction measurement of melt-spun ribbons and thin films by fiber-optic interferometry (광섬유 간섭계를 이용한 급속응고리본과 박막의 자기변형 측정)

  • Kim, Min-Hyoung;Jeong, Kyu-Cheol;Lee, Kyung-Shik;Lim, Sang-Ho
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1914-1916
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    • 1997
  • 광섬유 간섭계를 이용하여 급속응고 리본 및 박막의 자기변형을 측정하였다. 급속응고 리본인 METGLAS 2826MB의 자기변형값은 보고된 값과 매우 잘 일치하였다. 또한 광섬유에 박막코팅된 거대 자기변형재료의 하나인 Sm-Fe계 합금의 자기변형값을 측정하였다.

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Displacement sensor for Measuring magnetostriction of Amorphous Ribbon (비정질 리본의 자기변형 측정용 광섬유 변위센서)

  • 유권상;김철기;김중복;김현아
    • Journal of the Korean Magnetics Society
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    • v.6 no.1
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    • pp.36-39
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    • 1996
  • We have constructed a disp1acerrent sensor for measuring dynamic magnetostriction of an arrvrphous ribbon under alternating magnetic field using fiber optic Fabry-Perot interferorreter. The signal of the sensor was depen¬dent on the index matching oil and the optical isolator. The resolution of the sensor was $30{\AA}$ and the measured peak to peak magnetostriction of the amorphous ribbon $Fe_{81}B_{13.5}Si_{3.5}C_{2}$ was $28{\times}10^{-6}$.

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Optical Tensile-Strain Sensor using Depolarized Guided Acoustic-Wave Brillouin Scattering (간단한 구조를 갖는 Depolarized-GAWB산란을 이용한 광섬유 변형율 센서)

  • Kim, Bu-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.1
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    • pp.57-61
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    • 2008
  • A tensile-strain measurement method is proposed based on Depolarized Guided Acoustic-wave Brillouin Scattering (DGAWBS). The effect of tensile-strain applied to an optical fiber is investigated experimentally, observing that the resonance spectrum increases the measurement accuracy of DGAWBS at the TR25 mode. This paper presents a simple structure as tensile-strain sensor using two analyzers after sensing fiber.

Tensile Strength-Strain Relationship of Various Geogrids (다양한 지오그리드의 인장강도-인장변형 관계 특성)

  • Han, Sang-Hyun;Yea, Geu-Guwen;Lee, Kwang-Wu
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.2
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    • pp.83-93
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    • 2012
  • Since reinforced soil walls were introduced in domestic civil engineering society in early 1980's, various reinforcing materials including metal strips, bar mats, and sheet-type reinforcement using geotextile, geogrid, and etc. have been developed for construction purpose. Especially, the geogrid has been mostly used as a reinforcement for reinforced earth structures. This paper describes the tensile behaviors of four types of domestic geogrids. Also, a series of the wide-width tensile tests on three types of geogrids were conducted to assess the reliability of the tensile strains in geogrid measured by strain gauge. The tensile strain by strain gauge is larger than real strain of the geogrid and a difference between strain gauge reading and real strain non-linearly increase with increasing the tensile strain. However, when the tensile strain is smaller than 3%, a difference between strain gauge reading and real strain is negligible.

Strain Analysis in the Skin and Core Layers of Cross-Ply Composite Laminates Using A-EFPI Optical Fiber Sensor (광섬유 A-EFPI 센서를 이용한 직교적층 복합재료의 표피층 및 내부층의 변형률 해석)

  • 우성충;박래영;최낙삼;권일범
    • Composites Research
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    • v.17 no.5
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    • pp.15-24
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    • 2004
  • Longitudinal strains (${\varepsilon}_x$) of the core and skin layers in glass fiber reinforced plastic (GFRP) cross-ply composite laminates have been measured using the embedded optical fiber sensor of absolute extrinsic Fabry-Perot interferometer (A-EFPI). Transmission optical microscopy was used to investigate the damage behavior around the A-EFPI sensor. Foil-type strain gauges bonded on both the upper and lower surfaces were used for the measurement of the surface strains. It was shown that values of ${\varepsilon}_x$ in the interior of the skin layer and the core layer measured by embedded A-EFPI sensor were significantly higher than that of the specimen surface measured by strain gauges. The experimental results agreed well with those from finite element analysis on the basis of uniform stress model. Large strains in the core layer led to the occurrence of many transverse cracks which drastically reduced the strain at failure of optical fiber sensor embedded in the core layer.

Estimation of Rutting Property of Artificially-Aged Asphalt Mixtures Based on LMS(%) and $S_D$ (LMS(%)와 $S_D$에 의한 노화 아스팔트 혼합물의 소성번형 추정)

  • Jung, Jae-Hun;Park, Tae-Won;Doh, Young-Soo;Kim, Kwang-Woo
    • International Journal of Highway Engineering
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    • v.9 no.3
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    • pp.123-134
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    • 2007
  • This study was carried out for evaluating correlation of aging level and deformation resistance of asphalt mixtures conditioned by artificial aging treatment. The specimens were made of the short-term aged loose asphalt mixture which was kept in a convection oven at $154^{\circ}C$ for 2 hours, and then were artificially aged at $110^{\circ}C$ for 24, 48, 72 and 96 hours for long-term aging. Deformation strength ($S_D$) and large molecular size ratio (LMS(%)) were measured after short-term and each long-term aging treatment to evaluate aging extents of each mixture with aging time using GPC(Gel-permeation chromatograph) test. It is shown that the $S_D$ and LMS(%) were increased with aging time increment, and that LMS(%) quantity and $S_D$ have relatively good correlation each other. This study found that the aged asphalt mixture had better resistance against rutting and it was possible to estimate rutting characteristics of asphalt mixtures by using LMS(%) without a binder recovery.

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Optical Analysis in Particle Image Processing of Rotating Flow (회전유동의 입자화상처리시 광학적 해석)

  • 김유곤
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.7
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    • pp.53-65
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    • 1995
  • 입자화상 처리기법은 유체역학 분야의 정량적 유동가시화에 있어서 중요한 역할을 하고 있다. 회전 유동의 측면 사진을 찍을 때, 측정부의 볼록면 때문에 그 영상에서 광학적 변형이 일어나게 된다. 이러한 변형은 측정부의 형상은 물론 회전유동의 방향에 의해서도 큰 영향을 받는다. 정확한 유동장을 얻기 위해서 이러한 변형이 적절한 방법에 의하여 교정된다. 교정한 실험 데이터를 수치해석 결과와 비교해 보면 정량적으로 잘 맞는 것을 알 수 있다.

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