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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fiber optic methods for nondestructive testing

Rudraraju, Sridhar 10 January 2009 (has links)
This thesis demonstrates the use of fiber optic methods for nondestructive testing of composite materials and aluminum specimens using the acousto-ultrasound approach. A noncontact method using a hybrid interferometer is devised for measuring absolute surface acoustic wave (SAW) amplitudes. The J1..J4 spectrum analysis technique is used for calibrating the piezoelectric transducer cylinder (PZT) and JO/J2 spectrum analysis technique is used for demodulating the SAW signal from the interferometer. An extrinsic Fabry-Perot interferometric (EFPI) sensor is utilized for sensing acoustic emission, measuring speed and attenuation in aluminum and composite specimens. A broadband preamplifier is designed for amplifying signals from the EFPI sensor. Theoretical and practical minimum detectable air gap change of an EFPI sensor are calculated for the system. The directional sensitivity of the EFPI sensor to SAW is studied. / Master of Science

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