An electronic speckle pattern interferometer for two-dimensional strain measurement

ABSTRACTA new design for a thin film microtensile tester is presented. The strain is measured directly on the free-standing thin film from the displacement of laser spots diffracted from a thin grating applied to its surface by photolithography. The diffraction grating is two-dimensional, allowing strain measurement both along and transverse to the tensile direction. In principle, both Young's modulus and Poisson's ratio of a thin film can be determined. Ag thin films with strong <111> texture were tested. The measured Young moduli agreed with those measured on bulk crystals, but the measured Poisson ratios were low, most likely due to slight transverse folding of the film that developed during the test.

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Two-dimensional quantification of the corrosion process in metal surfaces using digital speckle pattern interferometry

Applied Optics ◽

10.1364/ao.50.001323 ◽

2011 ◽

Vol 50 (10) ◽

pp. 1323 ◽

Cited By ~ 5

Author(s):

N. Andrés ◽

J. Lobera ◽

M. P. Arroyo ◽

L. A. Angurel

Keyword(s):

Metal Surfaces ◽

Speckle Pattern ◽

Corrosion Process ◽

Two Dimensional ◽

Digital Speckle Pattern Interferometry ◽

Digital Speckle

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A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation

Metrology and Measurement Systems ◽

10.1515/mms-2016-0028 ◽

2016 ◽

Vol 23 (3) ◽

pp. 461-480 ◽

Cited By ~ 36

Author(s):

Sze-Wei Khoo ◽

Saravanan Karuppanan ◽

Ching-Seong Tan

Keyword(s):

Digital Image Correlation ◽

Digital Image ◽

Strain Measurement ◽

Surface Deformation ◽

Optical Measurement ◽

Image Correlation ◽

Two Dimensional ◽

Full Field ◽

Computation Efficiency ◽

Dimensional Measurements

Abstract Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

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Measurement of Mechanical Strain Using Chromatic Monitoring of Photoelasticity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.24-25.123 ◽

2010 ◽

Vol 24-25 ◽

pp. 123-128 ◽

Cited By ~ 2

Author(s):

Claudia Garza ◽

Anthony G. Deakin ◽

G.R. Jones ◽

J.W. Spencer ◽

K.K.B. Hon

Keyword(s):

Strain Measurement ◽

Mechanical Strain ◽

Ccd Camera ◽

Signal Strength ◽

Measurement Range ◽

Two Dimensional ◽

Effective Wavelength ◽

Signal Wavelength ◽

Present Contribution ◽

Chromatic Processing

The present contribution describes a chromatic processing approach for quantifying the two dimensional, polychromatic interference patterns produced by a strained photo-elastic element and recorded with a CCD camera. The outputs from the three R, G, B channels of the camera covering a selected area of the interference pattern are processed to yield three chromatic parameters which are H (dominant signal wavelength), L (nominal signal strength), S (effective wavelength spread of signal). It is shown that the value of each of the three parameters varies with strain in a quasi cyclical manner, all being out of phase with each other. Consequently the strain measurement range and sensitivity can both be optimized by the use of the appropriate chromatic parameter within different strain ranges.

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Investigation of Effect of Grains on Deformation of Wood under Shearing Loads Using Electronic Speckle Pattern Interferometry

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.43 ◽

2006 ◽

Vol 326-328 ◽

pp. 43-46

Author(s):

Eisaku Umezaki

Keyword(s):

Pseudotsuga Menziesii ◽

Speckle Pattern ◽

Electronic Speckle Pattern Interferometry ◽

Two Dimensional ◽

Annual Rings

The two-dimensional deformation of wood with different grains under shearing loads was measured using an electronic speckle pattern interferometry (ESPI) technique. The radical, tangential and end sections of Douglas firs (Pseudotsuga menziesii) were used as specimens. Results revealed that the deformation values significantly vary for every part of the specimens, and the ring directions of earlywood and latewood, which compose the annual rings, have an effect on the two-dimensional deformation of wood.

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