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dc.contributor.authorSwacek, Christian Bernharden_US
dc.date.accessioned2013-01-17T21:21:02Z
dc.date.available2013-01-17T21:21:02Z
dc.date.issued2012-08-27en_US
dc.identifier.urihttp://hdl.handle.net/1853/45812
dc.description.abstractConventional contact ultrasonic methods suffer from large variability, which is known to originate from a number of sources such as coupling variability, and the surface roughness at the transducer/specimen interface. The inherently small higherharmonic signals can be significantly influenced by the changes in contact conditions, especially in nonlinear ultrasonic measurements. For this reason, the noncontact generation and detection techniques are very attractive. This research first focuses on the optical generation of tone-burst surface acoustic waves in a metallic specimen. Two methods that use laser light as an optical source are compared for generating surface acoustics waves in the 5 MHz range. Both the shadow mask and diffraction grating are used to convert a laser pulse to a tone-burst signal pattern on the specimen. The generated signals are detected by a wedge transducer at a fixed location and then the harmonic contents in the generated signals and the repeatability of the methods are evaluated. Finally, the developed method is used to characterize the material nonlinearity of aluminum (Al 6061) and steel (A36). The results showed repeatable measurements for ablative signal excitation on aluminum.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectLaser excitationen_US
dc.subjectRayleigh wavesen_US
dc.subjectNoncontact excitationen_US
dc.subjectNonlinear acousticsen_US
dc.subject.lcshAcoustic surface waves
dc.subject.lcshUltrasonic waves Industrial applications
dc.subject.lcshUltrasonic testing
dc.subject.lcshUltrasonics
dc.titleOptical generation of tone-burst Rayleigh surface waves for nonlinear ultrasonic measurementsen_US
dc.typeThesisen_US
dc.description.degreeMSen_US
dc.contributor.departmentCivil and Environmental Engineeringen_US
dc.description.advisorCommittee Chair: Jacobs, Laurence; Committee Member: DesRoches, Reginald; Committee Member: Kim, Jin-Yeonen_US


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