• 제목/요약/키워드: Shearography

검색결과 66건 처리시간 0.043초

Shearography를 이용한 비파괴 검사 (Nondestructive Testing with Shearography)

  • 장석원
    • 비파괴검사학회지
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    • 제21권2호
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    • pp.177-181
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    • 2001
  • 광학적 비접촉 비파괴검사 방법인 ESPI, Shearography를 이용한 측정은 자동차나 항공기산업 등에서 최근 폭넓게 이용되고 있다. 빠른 측정 속도와 측정 대상의 전 영역을 한번에 측정할 수 있는 장점을 가진 Shearography를 이용한 비파괴검사 방법을 기존의 광계측법인 ESPI와 비교하였다. 또한 이러한 장점을 살려 산업현장에서 수행한 여러 가지 비파괴검사 사례를 제시하였다.

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직조 CFRP 복합재료 내부결함의 정량적 평가를 위한 Shearography 영상처리 기법 연구 (Study of Shearography Imaging for Quantity Evaluation Defects in Woven CFRP Composite Materials)

  • 최상우;이준현;이정호;변준형
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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    • pp.211-214
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    • 2001
  • Electronic Speckle Pattern Interferometry(ESPI) is one of optical technique to measure displacement precisely, uses CCD camera to show result image in real time. General ESPI system measures in-plane or out-of-plane displacement. Shearography is one of electronic speckle pattern interferometric methods which allow full-field observation of surface displacement derivatives and it is robust in vibration. The shearography provides non-contacting technique of evaluating defects nondestructively. In this study, the shearography was used to evaluate defects in Carbon Fiber Reinforced Plastic(CFRP). Various sizes of artificial defects were embedded in various depths of woven CFRP plate. Effects due to the variation of size and depth of defects were evaluated in this study.

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CFRP에 내재된 결함의 비파괴 평가를 위한 Shearography기법 적용 (Application of Shearography for Nondestructive Evaluation of Internal Defects in CFRP)

  • 최상우;이준현
    • 한국신뢰성학회:학술대회논문집
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    • 한국신뢰성학회 2002년도 정기학술대회
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    • pp.245-251
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    • 2002
  • Electronic Speckle Pattern Interferometry(ESPI) is one of optical technique to measure displacement precisely, uses CCD camera to show result image in real time. General ESPI system measures in-plane or out-of-plane displacement. Shearography is one of electronic speckle pattern interferometric methods which allow full-field observation of surface displacement derivatives and it is robust in vibration. The shearography provides non-contacting technique of evaluating defects nondestructively In this study, the shearography was used to evaluate defects in Carbon Fiber Reinforced Plastic(CFRP). Various sizes of artificial defects were embedded in various depths of woven CFRP plate. Effects due to the variation of size and depth of defects were evaluated in this study.

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이중기능 간섭계에 의해 측정된 면외변형의 정략적 비교 (Quantitative Comparison of Out-of-Plane Deformation Measured by Dual-Function Interferometer System)

  • 김경석;장호섭;이승석;정현철;곽재호
    • 비파괴검사학회지
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    • 제28권1호
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    • pp.33-39
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    • 2008
  • 이중기능 간섭계는 ESPI와 전단간섭계의 모든 기능이 하나의 간섭계로 구성되어 있다. ESPI는 대상물의 변형을 측정하고 전단간섭계는 대상물의 변형의 기울기를 측정한다. 제안된 전단간섭법은 전단간섭계의 결과를 평행이동시킨 화소수로 나누고, 적분하면 원래의 변형과 거의 같은 결과를 얻을 수 있는데 이를 ESPI의 결과와 비교하였다. 본 연구에서는 고무판과 알루미늄 시험편을 이용하여 이중기능간섭계로 동시에 두 기법의 면외변형 결과를 측정하여 비교하였다. 이중기능간섭계는 동일한 한번의 변형에 두 가지의 결과를 동시 측정함으로써 두 기법의 정확한 비교가 가능하였다. 본 연구에서는 제안된 전단간섭법과 ESPI의 결과를 이중기능 간섭계를 이용하여 정량계측하여 만족한 결과를 도출하였다.

Shearography의 1차도함수로부터 면외변위의 정량적 추출 (Quantitative Determination of Out-of-plane Displacement by Shearography)

  • 김경석;윤홍석;박찬주;최정석
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.772-776
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    • 2004
  • The paper describes the quantitative determination of out-of-plane displacement from result of Shearogrpahy, which can measure the first-order partial derivative of out-of-plane displacement directly. However, the differential sensitivity of Shearography is related to the amount of shearing, which is manually adjustable in optical interferometer and affects the quantitative determination. The relationship between those is inspected by comparing ESPI with Shearography. From the result, the amount of shearing plays a modulation factor of out-of-plane displacement and small amount of shearing gives good agreement with out-of-plane displacement.

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Digital shearography를 이용한 내부결함 검출에 있어서 전단량과 내부압력 변화에 따른 간섭줄무늬 패턴 분석 (The analysis of interferometry fringe pattern under shearing quantity and inside pressure change for inspect inside defects using by digital shearography)

  • 김형택;김경석;홍진후;강기수
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.140-143
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    • 2001
  • Digital shearography, a speckle pattern method is based on the superposition of two laterally sheared images. Therefore, object points which are positioned in some distance from each other are superposed in the image plane. This shearography, one of NDT methods without contact, is able to inspect defects in pipelines and pressure vessels that are used in nuclear power plants. This is can inspect whole fields and has a low sensitivity to environmental noise. Because optical setting is very simple, it has a little exhaustion of time, cost and man power. And also it can find a defect position through real time monitoring of a part. This paper, finds out the relationship among shearing quantity image quality and defect size with this method.

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미소변형 해석을 위한 Dual-beam Shearography (Strain Analysis by Dual-beam Shearography)

  • 김경석;최태호;김성식;최정석
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.251-254
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    • 2003
  • In recent years, shearogrpahy has significantly improved capabilities In the areas of unbend and separation detection in tires. Although shearography has many advantages fur qualitative evaluation, the technique remains the problem of quantitative analysis of inside defects, because shearography needs several effective factors including the amount of shearing, shearine direction and induced load, which exist as barrier for the quantitative analysis of inside defects. Since the factors are highly dependent on inspectors skill and also affect the in-situ workability. The factors were optimized and the size of cracks inside of pipeline and tire has been quantitatively determined.

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파장판을 이용한 Shearography의 위상천이기술에 대한 이론적 고찰 (The Theoretical Analysis about the Phase-Shifting Technique of Shearography Using Waveeplates)

  • 김수길
    • 조명전기설비학회논문지
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    • 제18권6호
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    • pp.8-13
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    • 2004
  • 본 논문에서는 Wollaston prism을 이용한 Shearography에서 수동소자인 두 개의 Waveplate와 편광판의 조합을 통해 각각 90도의 위상천이를 가지는 4개의 스펙클 패턴을 얻고, 이로부터 스펙클의 각 지점에서의 위상을 얻을 수 있는 방법을 제시하고, Jones 행렬을 이용하여 이론적으로 입증하였다.