• Title/Summary/Keyword: Out-of-plane ESPI

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A Study on the Strain Measuring of Structure Object (전자처리 및 Laser 간섭에 의한 구조물의 Strain측정에 관한 연구)

  • 김경석;최형철;양승필;정현철;김정호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.267-272
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    • 1993
  • This paper presents the performance and problems in analysis method and testing system of Electronic Speckle Pattern Interferometry (ESPI) method, in measuring two-dimensional in-plane displacement. The anyalysis result of measurement by ESPI is quite comparable to that of measurement by strain gauge method. This implieds that the method of ESPI is a very effective tool in non-contact two-dimensional in-planc strain analysis. But there is a controversal point,measurment error. This error is discussed to be affected not by ESPI method itseif, but by its analysis scheme of the interference fringe,where the first-order interpolation has been applied to the points of strain measured. In this case, it is turned out that the more errors would be occured in the large interval of fringe. so, this paper describes a computer method for drawing when the height is available only for some arbitary collection of points, the method is based on a distance-weighted, least-squares approximation technique, with the weight varying with the distance of the data points.

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Nodal pattern analysis of plane plate by using ESPI (ESPI를 이용한 평판의 Nodal Pattern 해석)

  • 김경석;정현철;양승필;김정호;이도윤;김태열;김형택
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.377-383
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    • 1996
  • Recently, a new technique called Electronic Speckle Pattern Inteferometry(ESPI) has been developed to overcome the drawbacks of existing holography. This technique enable real-time interference fringes to be displayed directly on TV monitor without recourse to any form of photographic processing. This research was carried out for the purpose of applying the vibration analysis method employing Electronic Speckle Pattern Interference technique to the vibration analysis of uniform rectangular cantilever plate, The natural vibration frequencies found by ESPI were in fair agreement with theoretical eigen frequencies acquired using theoretical formula G. B. Warburton proposed.

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A Study on the Inner Defect Inspection for Semiconductor Package by ESPI (ESPI를 이용한 반도체 패키지 내부결함 검사에 관한 연구)

  • Jung, Seung-Tack;Kim, Koung-Suk;Yang, Seung-Pil;Jung, Hyun-Chul;Lee, You-Hwang
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1442-1447
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    • 2003
  • Computer is a very powerful machine which is widely using for data processing, DB construction, peripheral device control, image processing etc. Consequently, many researches and developments have progressed for high performance processing unit, and other devices. Especially, the core units such as semiconductor parts are rapidly growing so that high-integration, high-performance, microminiat turization is possible. The packaging in the semiconductor industry is very important technique to de determine the performance of the system that the semiconductor is used. In this paper, the inspection of the inner defects such as delamination, void, crack, etc. in the semiconductor packages is studied. ESPI which is a non-contact, non-destructive, and full-field inspection method is used for the inner defect inspection and its results are compared with that of C-Scan method.

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

  • Kim, Koung-Suk;Yoon, Hong-Seok;Park, Chan-Ju;Choi, Jung-Suk
    • Proceedings of the KSME Conference
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    • 2004.11a
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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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Application of Shearography for Nondestructive Evaluation of Internal Defects in CFRP (CFRP에 내재된 결함의 비파괴 평가를 위한 Shearography기법 적용)

  • 최상우;이준현
    • Proceedings of the Korean Reliability Society Conference
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    • 2002.06a
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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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Study of Shearography Imaging for Quantity Evaluation Defects in Woven CFRP Composite Materials (직조 CFRP 복합재료 내부결함의 정량적 평가를 위한 Shearography 영상처리 기법 연구)

  • 최상우;이준현;이정호;변준형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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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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A Study on the Development of Image Processing Measurement System for Structural Analysis by Optical Non-contact Measurement (광학적 비접촉 측정에 의한 구조물 해석의 화상처리 계측 시스템 개발에 관한 연구)

  • Jang, Soon-Suck;Kim, Koung-Suk;Hong, Jin-Who;Choi, Ji-Eun;Kang, Ki-Soo;Kim, Dal-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.7
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    • pp.149-154
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    • 2001
  • This study discusses a non-contact optical technique, electronic speckle pattern interferometry(ESPI), that is well suited for a deformation measurement of structure. Phase shifting method and unwrapping method have used to make deformation quantitative widely. In this paper, a previous numerical formula for phase shifting method is reconstructed in addition to least square fitting method to improve sensitivity and phase unwrapping based on vertical-horizontal scanning method is applied to analyze in-plane and out-of-plane deformation quantitatively.

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A study on Sinusoidal Phase Modulating interferometer using laser diode (레이저 다이오드를 이용한 정현적 위상변조 간섭계에 대한 연구)

  • Pyo K.Y.;Park N.G.;Lee G.Y.;Kang Y.J.;Kim K.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.926-929
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    • 2005
  • Recently, laser interferometer is widely used as a measuring system in many fields because of its high resolution and its ability to measure a board area in real-time ail at once. In conventional laser interferometer, for examples Out of plane ESPI, In plane ESPI, Shearography and Holography, it uses PZT or other components as a phase shift instrumentation to extract 3-D deformation data, vibration mode and others. However, in most cases PZT has some disadvantages, which include noli-linear errors and limited time of use. In present study, a new type of laser interferometer using a laser diode(LD) is proposed. Using Laser Diode Sinusoidal Phase Modulating(LD-SPM) interferometer, the phase modulation can be directly modulated by controlling the LD injection current thereby eliminating the need for PZT components.

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Resonant vibration of piezoceramic plates in fluid

  • Lin, Yu-Chih;Ma, Chien-Ching
    • Interaction and multiscale mechanics
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    • v.1 no.2
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    • pp.177-190
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    • 2008
  • In this paper, both experimental measurement and theoretical analysis are used to investigate the out-of-plane resonant characteristics of a cantilevered piezoceramic plate in air and three different kinds of fluid. The experimental method, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), is the major technique used in this study to measure the resonant characteristics of the cantilivered piezoceramic plate. Both resonant frequencies and full-field mode shapes are obtained from this experimental technique. Numerical computations based on the finite element analysis are presented for comparison with the experimental results. Good quality of mode shapes for the cantilevered piezoceramic plate in air is obtained from the AF-ESPI technique. However, the quality decreases as the viscosity of fluids increases. From the results provided from experimental measurements and numerical computations, it is indicated that the resonant frequencies of the cantilevered piezoceramic plate in fluid decrease with the increase of the viscosity of fluids. Good agreements between the experimental measured data and the numerical calculated results are found for both resonant frequencies and mode shapes of the cantilevered piezoceramic plate in fluid.