<div class="csl-bib-body">
<div class="csl-entry">Agbodjan Prince, J. K. (2016). <i>Omnidirectional interferometric strain sensors for lamb wave detection</i> [Dissertation, Technische Universität Wien]. reposiTUm. https://doi.org/10.34726/hss.2016.37335</div>
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dc.identifier.uri
https://doi.org/10.34726/hss.2016.37335
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/4750
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dc.description
Zusammenfassung in deutscher Sprache
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dc.description.abstract
This thesis deals with a highly responsive method for detecting guided elastic waves, which is a promising means of non-destructive monitoring of large, preferably plate-like composite structures. Aiming at operation in environments of high electromagnetic activity, a double Michelson interferometer composed of fiber-optic components forms the core of the wave strain transduction system. The investigated interferometer employs a 33 fiber-optic directional coupler for splitting and recombinating optical waves. A segment of optical fiber that is preferably attached to the surface of the monitoring body carrying the elastic wave forms the measurement arm of the interferometer while a separate segment serves as reference. The directional characteristic of the strain transduction varies between pronounced directional or omnidirectional depending on the straight or circular shape of the attached fiber segment, respectively. Multi-turn spiral coiled fiber segments enable extraordinary high strain resolution. The double interferometer technique offers pseudo-quadrature interferometer signals that enable rather uniform resolution over a wide range of fiber elongation. This research work examines the function, technical properties, and application related aspects of interferometric transducers using finite element analysis and analytical modeling. Basic system characteristics are confirmed by experiments. Fundamental questions related to the selected detection technique that will be answered by this thesis include achievable sensitivity and resolution, perturbations of the elastic waves introduced by the attached fiber segment and the distortions of the fiber-optic strain conversion by the finite length of interaction between fiber and structure. Among other results, a leading-edge strain resolution of 8 10-9 was achieved with a single-turn fiber-optic strain transducer without any optimization of the detection system. Finite element (FE) simulations proved that attached fiber coils induce very moderate reflection and mode conversion so that a 10-turn fiber coil exhibits twice the elongation of a 5-turn coil. The transducer output signal becomes temporarily deformed compared to the wave strain if the wavelength of the surface strain approximates a fraction of the coil dimension.
en
dc.language
English
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dc.language.iso
en
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dc.rights.uri
http://rightsstatements.org/vocab/InC/1.0/
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dc.subject
Lamb wave detection
en
dc.subject
FE simulation
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dc.title
Omnidirectional interferometric strain sensors for lamb wave detection
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dc.type
Thesis
en
dc.type
Hochschulschrift
de
dc.rights.license
In Copyright
en
dc.rights.license
Urheberrechtsschutz
de
dc.identifier.doi
10.34726/hss.2016.37335
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dc.contributor.affiliation
TU Wien, Österreich
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dc.rights.holder
Just Kpoti Agbodjan Prince
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dc.publisher.place
Wien
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tuw.version
vor
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tuw.thesisinformation
Technische Universität Wien
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tuw.publication.orgunit
E366 - Institut für Sensor- und Aktuatorsysteme
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dc.type.qualificationlevel
Doctoral
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dc.identifier.libraryid
AC13408699
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dc.description.numberOfPages
118
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dc.identifier.urn
urn:nbn:at:at-ubtuw:1-91803
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dc.thesistype
Dissertation
de
dc.thesistype
Dissertation
en
dc.rights.identifier
In Copyright
en
dc.rights.identifier
Urheberrechtsschutz
de
tuw.advisor.staffStatus
staff
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item.openaccessfulltext
Open Access
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item.openairecristype
http://purl.org/coar/resource_type/c_db06
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item.grantfulltext
open
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item.mimetype
application/pdf
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item.languageiso639-1
en
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item.openairetype
doctoral thesis
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item.fulltext
with Fulltext
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item.cerifentitytype
Publications
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crisitem.author.dept
E384 - Institut für Computertechnik
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crisitem.author.parentorg
E350 - Fakultät für Elektrotechnik und Informationstechnik