Measurement of Strain by Digital Shearography with a New Algorithm of Phase Calculation

Document Type : Research Article

Authors

1 Department of Mechanical Engineering, University of Zanjan, Zanjan, Iran

2 Department of Physic, University of Zanjan, Zanjan, Iran

Abstract

ABSTRACT: In this paper, digital shearography method has been used to measure the in-plane strain. One
intensity is being recorded before loading and four intensities have been gotten after loading with the phase shifting
method. With the subtraction of first intensity from the four intensities of after loading, four new intensities being
calculated which from them the needed phase calculated and with use of this phase in the strain formula, the strain
can be calculate. For this work, the modified Michelson system as a shearing tool is used. Testing specimen was
an aluminum plate with the dimension of 35×35×1mm which is clamped in the boundary and has been loaded in
the center. For the loading, a fixture has been made which has the ability of 3-micron displacement creation. For
illumination on the specimen from two mutual and same directions, two diode lasers with the wavelength of 630 nm
are used as the optical source. Taking into account that in the experimental measurement the conditions are real but
are ideal in the numerical analysis, behavior of two graph of experimental measurement and numerical analysis is
approximately the same. In the part of error analysis, the amount of relative error is approximately 18% determined.

Keywords

Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 50, Issue 1
May and June 2018
Pages 25-32

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