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dc.contributor.advisorMichaels, Jennifer E.
dc.contributor.authorLevine, Ross M.
dc.date.accessioned2014-05-22T15:26:32Z
dc.date.available2014-05-22T15:26:32Z
dc.date.created2014-05
dc.date.issued2014-03-10
dc.date.submittedMay 2014
dc.identifier.urihttp://hdl.handle.net/1853/51829
dc.description.abstractStructural health monitoring (SHM) is concerned with the continuous, long-term assessment of structural integrity. One commonly investigated SHM technique uses guided ultrasonic waves, which travel through the structure and interact with damage. Measured signals are then analyzed in software for detection, estimation, and characterization of damage. One common configuration for such a system uses a spatially-distributed array of fixed piezoelectric transducers, which is inexpensive and can cover large areas. Typically, one or more sets of prerecorded baseline signals are measured when the structure is in a known state, with imaging methods operating on differences between follow-up measurements and these baselines. Presented here is a new class of SHM spatially-distributed array algorithms that rely on sparse reconstruction. For this problem, damage over a region of interest (ROI) is considered to be sparse. Two different techniques are demonstrated here. The first, which relies on sparse reconstruction, uses an a priori assumption of scattering behavior to generate a redundant dictionary where each column corresponds to a pixel in the ROI. The second method extends this concept by using multidimensional models for each pixel, with each pixel corresponding to a "block" in the dictionary matrix; this method does not require advance knowledge of scattering behavior. Analysis and experimental results presented demonstrate the validity of the sparsity assumption. Experiments show that images generated with sparse methods are superior to those created with delay-and-sum methods; the techniques here are shown to be tolerant of propagation model mismatch. The block-sparse method described here also allows the extraction of scattering patterns, which can be used for damage characterization.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technology
dc.subjectSparse reconstruction
dc.subjectLamb waves
dc.subjectGuided waves
dc.subjectStructural health monitoring
dc.subjectSmart structures
dc.subjectUltrasonic waves
dc.subjectNon-destructive evaluation
dc.subjectNon-destructive testing
dc.subject.lcshSparse matrices
dc.subject.lcshStructural analysis (Engineering) Matrix methods
dc.subject.lcshUltrasonic imaging
dc.subject.lcshUltrasonics
dc.subject.lcshNondestructive testing
dc.titleUltrasonic guided wave imaging via sparse reconstruction
dc.typeDissertation
dc.description.degreePh.D.
dc.contributor.departmentElectrical and Computer Engineering
thesis.degree.levelDoctoral
dc.contributor.committeeMemberMichaels, Thomas E.
dc.contributor.committeeMemberRomberg, Justin K.
dc.contributor.committeeMemberScott, Waymond R.
dc.contributor.committeeMemberRuzzene, Massimo
dc.date.updated2014-05-22T15:26:32Z


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