Relating crack heating to vibration for vibrothermography

dc.contributor.author Uhl, Christopher
dc.contributor.department Aerospace Engineering
dc.date 2018-08-25T02:50:12.000
dc.date.accessioned 2020-06-30T08:21:00Z
dc.date.available 2020-06-30T08:21:00Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2008
dc.date.embargo 2013-12-13
dc.date.issued 2008-01-01
dc.description.abstract <p>Vibrothermography is an inspection technique that detects cracks by observing vibration induced crack heating. Frictional crack heating in a vibrating specimen is directly linked to the resonant vibrational stress on the crack. In simple geometries we can measure the vibrational mode structure and intuit the dynamic vibrational stress field on the crack. This can be used to establish a relationship between crack heating and vibration, which will be critical for vibrothermography to be accepted as a viable inspection technology. We correlate stress to heating by exciting specimens in a well understood and repeatable resonant vibration mode. Through knowledge of the mode shape, a single point surface velocity measurement is sufficient to calculate the deformed shape of the entire specimen. The loads and stresses within the specimen are calculated from the deformed shape and used to identify the relationship between crack heating and vibration. We explore a simplified case of a bar in third order flexural resonance with a surface crack that heats in response to flexure-induced normal load. Specimens are tuned to resonate in third order flexural bending when excited with a single frequency excitation system. We present an observed relationship between dynamic normal stress, crack size, and crack heating.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/262/
dc.identifier.articleid 1259
dc.identifier.contextkey 4922753
dc.identifier.doi https://doi.org/10.31274/rtd-180813-5322
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/262
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/74193
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/262/2008_UhlCJ_RelatingCrackHeating.pdf|||Fri Jan 14 23:02:21 UTC 2022
dc.subject.disciplines Aerospace Engineering
dc.subject.keywords CNDE
dc.subject.keywords Nondestructive Evaluation
dc.title Relating crack heating to vibration for vibrothermography
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 047b23ca-7bd7-4194-b084-c4181d33d95d
thesis.degree.level thesis
thesis.degree.name Master of Science
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