• Title/Summary/Keyword: 전단간섭계

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

  • Kim, Kyoung-Suk;Chang, Ho-Seob;Lee, Seung-Seok;Jung, Hyun-Chul;Kwag, Jae-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.1
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    • pp.33-39
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    • 2008
  • Dual-function interferometer is an interferometer that has all features of ESPI (electronic speckle pattern interferometry) and shearography in one interferometer setup. The deformatiou of an object is directly obtained by ESPI while the slope of the deformation of an object is obtained by shearography. If the result of shearography is divided by shearing amount and integrated by numerical analyzing, then finally the reconstructed deformation of an object that is the same as the results directly obtained by ESPI can be measured by shearography. In this study, rubber and alruminum plates are used as specimen and its out-of-plane deformation is measured by ESPI and shearography setup of the dual-function interferometer. Each of the results obtained by ESPI and shearography is compared by using numerical integration to the result of shearography. From this study, it is confirmed that the reconstructed deformation results obtained by numerical integration good agree with the results obtained by ESPI.

Measuring limits of speckle shearing interferometer by double speckle interferometry (이중 스펙클 간섭계를 이용한 전단간섭계의 변형 측정 한계 측정)

  • Yoon Byung Gon;Yoon Jae Sun
    • Korean Journal of Optics and Photonics
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    • v.15 no.5
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    • pp.405-408
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    • 2004
  • In this paper, we used a split-lens speckle shear interferometer using a double speckle interferometer, which enables continuous measurement of the deformation. We made two identical specklegrams corresponding to an object. With this method we could detect the measuring limits of the deformation for various shears. This experimental results showed that the measuring limits of a split-lens speckle shear interferometer are similar to the measuring limits of a double exposure speckle interferometer.

Quantitative Measurement of Out-of-plane Deformation Using Shearography (전단간섭계를 이용한 면외변형의 정량적 계측)

  • Chang, Ho-Seob;Jung, Sung-Wook;Kim, Kyoung-Suk;Jung, Hyun-Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.4 s.193
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    • pp.131-137
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    • 2007
  • Electronic Speckle Pattern Interferometry(ESPI) is a common method for measuring out-of-plane deformation and in-plane deformation and applied for vibration analysis and strain/stress analysis. However, ESPI is sensitive to environmental disturbance, which provide the limitation of industrial application. On the other hand, Shearography based on shearing interferometer which is insensitive to vibration disturbance can directly measure the first derivative of out-of-plane deformation. In this paper a technique that extract out-of-plane deformation from results of shearography by numerical processing is proposed and measurement results of ESPI and Shearoraphy are compared quantitatively.

Deformation Measurement of Well Thinning Elbow by Using Shearography (전단간섭법을 이용한 감육 곡관부의 변형 계측)

  • Jung, Hyun-Chul;Kim, Koung-Suk;Chang, Ho-Sub;Jung, Sung-Wook;Kang, Ki-Soo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.5
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    • pp.321-328
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    • 2006
  • In this study, the deformation oi wall thinning elbow is measured and the position of the internal thinning defect is found out by shearography. Shearography is an optical method which has applied to nondestructive testing (NDT) and the strain/stress and deformation analysis. This technique has the merit of the directly measuring the first derivative of displacement with sensitivity which can be adjusted by handling the tilt mirror in the interferometer. In this paper, we tested carbon steel pipe locally wall thinned and loaded internal pressure and the shearography was applied to measure the out-of-plane deformation of wall thinning elbow and to investigate the internal thinning defect of it. From the results, it was confirmed that this technique is proper to the practical application on the pipe line system with internal defect.

Study of Development of Image Processing Algorithm for Measurement of Out of Plane Deformation Using the Shearography (전단간섭계를 이용한 내부 결함의 면외 변위 측정을 위한 화상처리 알고리즘 개선에 관한 연구)

  • Choi, In Young;Kang, Young June;Hong, Kyung Min;Kim, Sung Jong;Park, Jong Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.1
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    • pp.59-66
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    • 2013
  • The measuring of internal defects of objects using the shearography has many advantages. It is a non-contact and non-destructive method and It has a real time measurement speed and no constraints of object shape. Compared to ESPI(Electronic Speckle Pattern Interferometry), Shearography has a very low error rate by vibration and air turbulence. So shearography provides possibilities of industrial application. In this paper, Image processing algorithm that is measurement of out-of-plane deformation using the shearography is proposed by developed using the LabVIEW 2010 and measurement result of out-of-plane ESPI and Shearography are compared quantitatively.

Development of electronic shearography for vibration analysis (진동해석을 위한 전자전단간섭계의 개발)

  • Kang, Young-June;Kwon, Yong-Ki
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.12
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    • pp.2047-2054
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    • 1997
  • This paper describes a measuring method of vibration mode shapes by the Electronic Shearography. This method called the speckle interferometer has many merits in practical use, such as low sensitivity to environmental noise, low limit of coherent-length and simple optical configuration. In this study, we developed Michelson-type shearing interferometer provided with a phase stepping mirror and with a bias modulation mirror to quantify the vibration gradient fields. Results of application to a simple cantilever plate show that the vibration amplitude fields obtained are in good agreement with those of the electronic speckle pattern interferometry (ESPI).

A Study on Measurement of Internal Defects of Pressure Vessel by Digital Shearography(II) (전자 전단 간섭법을 이용한 압력용기의 내부결함 측정에 관한 연구(II) (전자 전단 간섭법을 이용한 압력용기의 내부결함 검출 시스템의 오차 분석))

  • Kang, Young-June;Park, Nak-Kyu;Ryu, Won-Jae;Kim, Dong-Woo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.4
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    • pp.402-410
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    • 2002
  • Recently the necessity of study on optical measuring method using laser to detect the pipeline's defect in nuclear facilities, chemical industries and power plants has been increased. Because laser light can be delivered to a remote area without any difficulties, the application of laser in many industries can solve several difficulties from the limitation of access in danger area and reduce the risks of workers. Therefore, we applied a new experimental technique to the measurement of internal defects in pressure vessels with the combination of shearography and image processing technique and detected the internal cracks of pressure vessels in the former paper. In this paper, we used the same optical system as in the former study and found the optimum shearing magnitude by comparing the real length of specimen with experimental results. A variety of conditions were applied to certify the validity of this method. Actually, several specimens which have different lengths and depths were used in this experiment under the three diverse pressure. Consequently, we have carried out this experiment to determine the limit of measurement ability with analyzing errors.