Thermal strain measurement by one-beam laser speckle interferometry

Chiang, Fu‐Pen; Anastasi, Robert F.; Beatty, J.; Adachi, Jiro

doi:10.1364/ao.19.002701

Cited by 12 publications

(5 citation statements)

References 3 publications

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“…Secondly, and more importantly, the straining of the specimen surface has caused decorrelation of the speckles. 25 The scattered light approach to measuring interior displacement is uniquely a speckle method in the sense that there is no moiré counterpart. While the method at the present stage is still at its infancy, one has reason to believe that it will some day bloom into a mature three-dimensional stress analysis method.…”

Section: Discussionmentioning

confidence: 99%

“…It can be shown8 that when such a photographic record is processed and Fourier transformed, the diffraction halo assumes the following intensity distribution. (25) (26) I(rx,ry) = Klt(rx,ry)jo2 ( 2Dk (+xrx + +yry)1 (27) where K' is a constant and Jo is again the zeroth order Bessel function of the first kind which modulates the original diffraction halo I,. Here dark fringes are observed when Jo is zero and bright fringes are where Jo attains either maximum or minimum.…”

Section: Stress Analysis Of Thin Plates Under Transverse Bending Usinmentioning

confidence: 99%

“…Here again if we denote rx and ry by r and let p = AL/r, the equations are the same as Eqs. (25) and (26) of the moire method. The only difference is the fact that fringe orders for bright and dark fringes are reversed.…”

Section: Three -Dimensional Stress Analysis By Moiré and Laser Specklmentioning

confidence: 99%

See 2 more Smart Citations

Optical Stress Analysis Using Moire Fringe And Laser Speckles

Chiang

1979

Opt. Eng

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The paper reviews a series of experimental stress analysis methods using moiré fringe and laser speckles. An analogy is drawn between the two groups of methods showing that moiré methods are special cases of speckle methods. Difference between the two approaches are also pointed out. The experimental methods discussed include the analysis of plane stress and general threedimensional problems, static and dynamic bending of plates, steady state vibration and transient stress problems.

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Section: Discussionmentioning

confidence: 99%

Section: Stress Analysis Of Thin Plates Under Transverse Bending Usinmentioning

confidence: 99%

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Optical Stress Analysis Using Moire Fringe And Laser Speckles

Chiang

1979

Opt. Eng

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“…ESPI is based on the slight changes in the scattered speckles determined by electronically subtracting the speckle patterns before deformation from those captured after deformation happened in the object [9]. ESPI has been applied to measure heating-induced deflection of the specimen [10][11][12]. The displacement discontinuity might occur on opposite sides of a crack under strains.…”

Section: Introductionmentioning

confidence: 99%

Crack detection in photovoltaic cells using electronic speckle pattern interferometry

Wen

Yin

2009

SPIE Proceedings

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This paper presents a full field nondestructive testing method to inspect the micro-defects embedded in photovoltaic (PV) cells by using electronic speckle pattern interferometry. The edge-clamped solar cells were heated to induce thermal deflection. Interference fringe enhanced by speckle patterns correlated to thermal deformation were determined by subtraction of two pictures recorded at different temperatures and image processing technique based on Fourier optics. The interference fringes produced at the defect free specimen exhibit a number of polygons with regular patterns of bright and dark fringes which are concentric with the center of the specimen. The thermal deformation will be redistributed due to appearance of the defects. The heating-induced interference fringes become quite different from those of the undamaged one. Tangential discontinuities of interference fringes or locally concentric polygon patterns occur in the contiguous area around the micro-defects or damages. The application of large temperature gradient to silicon substrates will induce crack propagation and should be prevented in ESPI inspection.

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“…Nevertheless, the quest continues. This is evident from methods utilizing holographic interferometry [10], speckle-based techniques [11][12][13][14][15][16][17], detection of the change in position of a laser beam [18], variable-area slits [19], modified push-rod dilatometers [20] and the Ronchi-grating approach [21].…”

Section: Introductionmentioning

confidence: 99%

A proposal for a referenceless approach to measurements of the thermal expansion of solids

Vikram¹

1997

Meas. Sci. Technol.

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A referenceless approach for thermal expansion and other dimensional stability measurement problems is established. The method is based on measuring the light intensity scattered by the uniformly illuminated surface. Since the change in intensity is proportional to the change in area such as that caused by thermal expansion, the procedure yields an excellent measurement tool. An aluminium surface is used to demonstrate the validity of the procedure practically. The thermal expansion coefficient determined experimentally is in close agreement with the expected value.

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Thermal strain measurement by one-beam laser speckle interferometry

Cited by 12 publications

References 3 publications

Optical Stress Analysis Using Moire Fringe And Laser Speckles

Optical Stress Analysis Using Moire Fringe And Laser Speckles

Crack detection in photovoltaic cells using electronic speckle pattern interferometry

A proposal for a referenceless approach to measurements of the thermal expansion of solids

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