• Title/Summary/Keyword: 홀로그래픽 간섭법

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The Measurment Method of Small Deformation by using Holographic Interferometry (홀로그래픽 간섭법을 이용한 미소변형 측정법)

  • Kang, Young-June;Moon, Sang-Joon
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.9
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    • pp.52-58
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    • 1995
  • Conventional measurement methods for non-destructive testing(NDT) in nuclear power plants and other industrial plants have been performed as the methods of contact with objects to be inspect, but those methods have been taken relatively much time to be inspected. Holographic interferometry which is a non-contact optical measurement method using a coherent light can overcome these demerit, and also has an advantage that the quantitative measurement of small deformation for large areas can be accomplished at a time with high precision. In this paper the comparisons of the experimental results form holographic interferometry with those from the finite element method(FEM) and the analytical solutions of the elastic equation are discussed.

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Strain analysis of cantilever beam under eccentric force using holographic interferometry (홀로그래픽 간섭법을 이용한 편심하중에 의한 외팔보의 변형률분포 해석)

  • 박승옥;김홍석;권혁홍;조동현
    • Korean Journal of Optics and Photonics
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    • v.8 no.1
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    • pp.14-18
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    • 1997
  • Using holographic interferometry, strain distributions for a cantilever beam subjected to the eccentric force can be analysed. Holographic fringe pattern shows inclined straight lines for the composite deformation of bending and torsion. Using these inclinations of the fringe pattern, 3rd order polynomial of plane displacements can be determined without difficulty. As the result, both of axial and shear strain distribution can be obtained from the second partial derivatives of this polynomial. These results agree well with FEM.

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레이저 계측

  • 조두진
    • 전기의세계
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    • v.42 no.6
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    • pp.26-31
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    • 1993
  • 레이저 계측의 광범위한 분야에서 홀로그래픽 간섭법과 전자스펙클무늬 간섭법을 중심적으로 살펴보았다. 이 방법들은 거친 표면을 갖는 다양한 물제에 대해 간섭적 방법에서 가능한 정밀도로 측정 할 수 있으므로 매우 폭넓은 응용가능성을 가지고 있고 지금도 새로운 아이디어들이 제시되고 있다. 특히 ESPI는 CCD카메라의 발전과 영상처리기술의 발전에 따라 피파괴검사 분야에서 중심적인 역할을 할 것으로 전망된다. 그러나 국내에서는 이제까지 이러한 첨단계측법들이 산업기술분야에서 별로 활용되지 못하고 있는 실정으로 가까운 장래에 큰 역할을 할 것으로 기대해 본다.

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홀로그래픽 간섭무늬에 의한 변형률 측정

  • 권혁흥;조동현;김흥석;박승옥;조대근;권영하
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.529-533
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    • 1994
  • Atrains in microstain range are measured accurately by means of holographic interometric technique. Holographic fringes of the cantilever beam subjected to out-of-plane deflection and in-plane deflection respectively are obtained experimentally. Form these fringe patterns, 3rd order polynomial of displacements is induced using polynomial regression method. And strain stress distribution could be determined from the secound derivative of this polynomial. These results agree well with FEM.

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A Study on the Measurement of Vibration Mode Shape using Holographic interferometry (홀로그래픽 간섭법을 이용한 진동모드의 계측에 관한 연구)

  • 김광래
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.3
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    • pp.130-135
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    • 2000
  • In this study the vibration behavior of the stiffened double cylinder was experimently analyzed. Due to the complex structure of the double cylinder the outside cylinder frequency responses to the exciting forces applied on various posi-tions were analyzed by using spectrum analyzer in conjunction with an accelerometer and the natural frequencies were obtained. The technique of time-averaged holographic interferometry is applied to study the vibration characteristics of outside cylinder with stiffening T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. however the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. However the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame seemed to behave as a transmitter. In addition it has been successfully demon-started that optical method such as holographic interferometry is well suited for the identification of mode shapes. They can give us a whole-field non-contact measurement instead of the point-wise measurement by accelerometer in classical modal testing.

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Measurement Method of the Vibration Mode Shapes Using Electro-Optic Holographic Interferometry (전자 광학적 훌로그래픽 간섭법을 이용한 진동물체의 모드형태 계측법)

  • Choi, Jang-Seob;Kang, Young-June
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.2
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    • pp.564-574
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    • 1996
  • This paper describes as Electronic Speckle Pattern Interferometry system which has been designed for measuring vibration patterns and quantitative measurement of vibration amplitude fields by using the time average method on a object. Visbility of fringe patterns is more improved by using the phase stepping and frame average method to reduce speckle and electric noise. And a bias vibration is introduced into the reference beam to shift the $\frac{2}{0}$ fringes so that fringe shift algorithms can be used to determine vibration amplitude. The experimental results are compared to those of the FFT analyzer and the FEM model analysis.

A Measurement Method of Internal Defects of Pressure Vessles by Using Real-Time Holographic Interferometry (실시간 홀로그래픽 간섭법을 이용한 압력용기의 내부결함 측정법)

  • Moon, Sang-Joon;Kang, Young-June;Baik, Sung-Hoon;Kim, Cheol-Jung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.1233-1240
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    • 1996
  • Conventional measurement methods using ultrasonic wave or x-ray, eddy current for non-destructive testing(NDT) in nuclear power plants and other industrial plants have been utilized as the method of contact with objects to be inspected. For this reason these methods require relatively much time and inspection area is limited by the location of probe or film. But holograpic interferometry which is a non-contact optical measurement method using a coherent light source has an advantage that quantative measurement can be performed at a time. In this paper a new method using realtime holographic interfreometry and image processing for detecting internal flaws of pressure vessels is presented.

Vibration Analysis of Loudspeaker by Using Electronic Speckle Pattern interferometry (전자 스페클 간섭계에 의한 스피커 진동 해석)

  • 강영준
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.1
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    • pp.92-99
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    • 1997
  • Nowadays, Electronic Speckle Pattern Interferometry is a well-established measuring technique with a wide range of industrial applications, particularly in the fields of deformation measurement and vibration analysis. Comparing with holographic interferometry, it has some attractive features, which are rapid recording and reconstruction, satisfiable automation etc. The Time-Average ESPI is used to provide vibration mode shape of an object whose vibration amplitude is given as a fringe pattern. Its merit is rapid and simple measurement for vibrating object. However, it is not possible to determine the direction of motions of a point on the object at any given time, because it does not give any information about the phase of vibration. But, Stroboscopic ESPI can measure the amplitude and phase of vibrating surface. In this paper, loudspeakers were tested by these two methods. As a result, we can assume that these techniques will be applied directly in the loudspeaker industry.

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Vibration Analysis of Loudspeaker by Using Electronic Speckle Pattern Interferometry (전자 스페클 간섭계에 의한 스피커 진동 해석)

  • 김정규;노경완;강영준;김동우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.356-361
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    • 1996
  • Nowadays, Electronic Speckle Pattern Interferometry is a well established measuring technique with a wide range of industrial applications, particularly in the fields of deformation measurement and vibration analysis. Comparing with holographic inteferometry, it has some attractive features, which are rapid recording and reconstruction, satisfiable automation etc. Time-average ESPI was used to provide vibration mode shape of an object whose vibration amplitude is given as a fringe pattern. However, it is not possible to determine the direction of motions of a point on the object at any given time, because time-average method does not give any information about the phase of vibration. A better technique is stroboscopic method which can measure the amplitude and phase of vibrating surface. In this paper, loudspeakers were tested by these two methods and the mode shape and amplitude of vibration were visualized. As measured results, we can assume that these techniques will be applied directly in the loudspeaker industry.

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Visualization and Measurement of Fluids with Real-time Holographic Interferometry (실시간 홀로그래픽 간섭법을 이용한 유체의 가시화)

  • Eom, Chul;Kang, Young-June;Kim, Dong-Woo;Ryu, Weon-Jae;An, Jung-Keun
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.539-544
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    • 2001
  • The holographic measurement techniques can be applied to various industrial fields such as automobile, airplane, construction, electronics, medical, mechanics and physics. The visualization of fluids is very important in aerodynamics, heat transfer and stress analysis. There are classically optical methods such as shadowgraph, schlieren method, and Mach-Zehnder interferometry for visualizing the fluid flow phenomena. But, it is difficult to understand the continuous state of fluids well in those methods. In this study, the real-time holographic interferometer with high-speed camera is applied to the flow visualization. In addition, collimated laser beam and rotating wedge are used for recording and formation of carrier fringes, respectively.

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