Effects of Crack Closure on Ultrasonic Transmission

dc.contributor.author Thompson, R. Bruce
dc.contributor.author Skillings, B.
dc.contributor.author Zachary, L.
dc.contributor.author Schmerr, L.
dc.contributor.author Buck, Otto
dc.date 2018-02-14T02:20:01.000
dc.date.accessioned 2020-06-30T06:29:17Z
dc.date.available 2020-06-30T06:29:17Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 1983
dc.date.issued 1983
dc.description.abstract <p>Ultrasonic waves are attenuated as they propagate past the tip of a crack due to the reflection of the energy at the crack face and diffraction at the crack tip. Crack closure modifies the situation since partial transmission can occur at points along the crack face where asperities come in contact. This phenomenon is important in defining the ability to nondestructively detect closed cracks and in developing a more detailed understanding of the closure phenomenon itself. Modified compact tension specimens were used to investigate the effects of partial crack closure on focussed, through-transmission ultrasonic signals. Data obtained from fatigue cracks in 7075-T651 A1 provides evidence for a gradual transition from a fully closed crack condition at the crack tip to an essentially fully open condition at a distance of a few mm from the tip, with additional localized contact along the length of the crack. This interpretation of the data was aided by a two-dimensional, quasi-static model for ultrasonic interaction with a partially contacting interface. The model relates width and separation of asperity contacts to the frequency dependence of the ultrasonic reflection and transmission. These measurements were supplemented by tests in which water infiltrated into the crack opening. The frequency spectra of the ultrasonic transmitted signals for this case were used to estimate the average COD at various points along the crack length.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/qnde/1983/allcontent/19/
dc.identifier.articleid 1018
dc.identifier.contextkey 5761596
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath qnde/1983/allcontent/19
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/58544
dc.language.iso en
dc.relation.ispartofseries Review of Progress in Quantitative Nondestructive Evaluation
dc.source.bitstream archive/lib.dr.iastate.edu/qnde/1983/allcontent/19/1983_Thompson_EffectsCrack.pdf|||Fri Jan 14 21:48:55 UTC 2022
dc.source.uri 10.1007/978-1-4613-3706-5_19
dc.subject.disciplines Acoustics, Dynamics, and Controls
dc.subject.disciplines Structural Materials
dc.subject.keywords Ames Laboratory
dc.title Effects of Crack Closure on Ultrasonic Transmission
dc.type event
dc.type.genre article
dspace.entity.type Publication
relation.isSeriesOfPublication 289a28b5-887e-4ddb-8c51-a88d07ebc3f3
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