Direct Strain and Slope and Slope Measurement Using 2D DSPSI

Abstract:

Large variety of optical full-field measurement techniques are being developed and applied to solve mechanical problems. Since each technique possesses its own merits, it is important to know the capabilities and limitations of such techniques. Among these optical full-field methods, interferometry techniques take an important place. They are based on illumination with coherent light (laser). In shearing interferometry the difference of the out of-plane displacement in two neighboring object points is directly measured. Since object displacement does not result in interferometry fringes, the method is suited for localization of strain concentrations and is indeed used in industry for this purpose. DSPSI possesses the advantage over conventional out-of-plane displacement-sensitive interferometry, that only a single difference of the unwrapped phase map is required to obtain flexural strains, thereby relieving problems with noise and reduction in the field of view. A first work in this domain (DSPSI) [1] was made in 1973, later recent studies emerged to provide a quantitative system of measurements [2]. This work aims to present the results of strain and slope measurements using digital speckle pattern shearing interferometry (DSPSI).

• Periodical: Advanced Materials Research (Volume 324)
• Pages: 384-387
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.324.384
• Online since: August 2011
• Authors: Wajdi Dandach, Jerome Molimard, Pascal Picart
• Keywords: Digital Speckle Pattern Shearing Interferometry, Interferometry, Optical Full-Field Technique (OFFT), Strain Measurements

References

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[2] S. Waldner, and N. Goudemand, in Speckle Light: Theory and Applications: Proceedings of the International Conference, Lausanne, Switzerland, 319-326 (2000).

[3] Aebischer, H.A. and Waldner, S., Optics and Lasers in Engineering, 26, pp.407-420, 1997.

[4] Post, D., Han, B. and Ifju, P., Springer, Berlin, Heidelberg, 1994.

[5] Pierron, F., design and experimental procedure, Internal Report n° 940125, Ecole des Mines de Saint-Etienne (France), 1994.