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Proceedings Paper

Robust shearography system for inspection of defects in composite material using diffractive optics
Author(s): Fabio A. A. da Silva; Daniel Willemann; Analucia V. Fantin; Mauro Benedet; Sérgio D. Soares; Armando Albertazzi
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Paper Abstract

The increasing industry demand for specialized materials promotes a breakthrough in material engineering. In this context, composite materials have gained recognition and have been increasingly employed in the most diverse segments of the industry. When applied to equipment with structural requirements, it is fundamentally important to periodically inspect these materials to ensure their integrity and safety. Often inspections are performed in the field, under unstable conditions generated by operational and environmental factors. Shearography is a valuable method of nondestructive testing (NDT) for industrial applications. This optical technique is less sensitive to environmental disturbances when compared to other interferometric techniques. This paper presents a new shearography configuration based on Diffractive Optical Elements (DOE). In the proposed configuration, a diffraction grating is positioned between the camera sensor and the imaging lens. Therefore, a more compact and robust system is obtained. Another advantage of the proposed system is related to phase shifting, which is generated by the lateral movement of the diffraction grating. Thus, phase shifting is relative to the diffraction grating period and not the laser wavelength as in traditional interferometers. This feature makes the system insensitive to variations in laser wavelengths. Since the period of the diffraction grating used is about 60 times greater than the laser wavelength applied, the shearography system using diffraction grating becomes much more robust for external influences compared to other configurations based on the Michelson interferometer. This paper also presents the evaluation of the proposed shearography system as well as prospective steps.

Paper Details

Date Published: 24 August 2017
PDF: 13 pages
Proc. SPIE 10376, Novel Optical Systems Design and Optimization XX, 103760O (24 August 2017); doi: 10.1117/12.2274138
Show Author Affiliations
Fabio A. A. da Silva, Univ. Federal de Santa Catarina (Brazil)
Daniel Willemann, Univ. Estadual de Santa Catarina (Brazil)
Analucia V. Fantin, Univ. Federal de Santa Catarina (Brazil)
Mauro Benedet, Univ. Federal de Santa Catarina (Brazil)
Sérgio D. Soares, PETROBRAS (Brazil)
Armando Albertazzi, Univ. Federal de Santa Catarina (Brazil)

Published in SPIE Proceedings Vol. 10376:
Novel Optical Systems Design and Optimization XX
Arthur J. Davis; Cornelius F. Hahlweg; Joseph R. Mulley, Editor(s)

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