Detecting the thickness mode frequency in a concrete plate using backward wave propagation
2016 (English)In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 139, no 2, 649-657 p.Article in journal (Refereed) Published
Material stiffness and plate thickness are the two key parameters when performing quality assurance/quality control on pavement structures. In order to estimate the plate thickness non-destructively, theImpact Echo (IE) method can be utilized to extract the thickness resonance frequency. An alternativeto IE for estimating the thickness resonance frequency of a concrete plate, and to subsequently enablethickness determination, is presented in this paper. The thickness resonance is often revealed as asharp peak in the frequency spectrum when contact receivers are used in seismic testing. Due to a lowsignal-to-noise ratio, IE is not ideal when using non-contact microphone receivers. In studying thecomplex Lamb wave dispersion curves at a frequency infinitesimally higher than the thickness frequency,it is seen that two counter-directed waves occur at the same frequency but with phase velocitiesin opposite directions. Results show that it is possible to detect the wave traveling with anegative phase velocity using both accelerometers and air-coupled microphones as receivers. Thisalternative technique can possibly be used in non-contact scanning measurements based on aircoupled microphones.
Place, publisher, year, edition, pages
Acoustical Society of America (ASA), 2016. Vol. 139, no 2, 649-657 p.
Thickness frequency, zero group velocity, backward wave propagation
Infrastructure Engineering Geotechnical Engineering
IdentifiersURN: urn:nbn:se:kth:diva-155909DOI: 10.1121/1.4941250ISI: 000373705300014ScopusID: 2-s2.0-84957576596OAI: oai:DiVA.org:kth-155909DiVA: diva2:763333
FunderSwedish Transport Administration
QC 201604122014-11-142014-11-142016-09-28Bibliographically approved