Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates using Coded Excitation Signals

Beitrag in einer Fachzeitschrift
(Review-Artikel)


Details zur Publikation

Autor(en): Kiefer DA, Fink M, Rupitsch S
Zeitschrift: IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
Jahr der Veröffentlichung: 2017
Band: 99
ISSN: 0885-3010
Sprache: Englisch


Abstract


Layer thickness and speed of sound are important parameters for non-destructive testing applications. If one of the parameters is known, the other one can be determined by simple time-of-flight measurement of ultrasound. However, often these parameters are both unknown. In this contribution, we examine and adapt ultrasonic imaging techniques using coded excitation signals to simultaneously measure the thickness and speed of sound in homogeneous elastic plates of unknown material. Good axial resolution is required to measure thin samples. We present a new approach for transmission signal conditioning to improve axial resolution. This conditioning consists of enhancing spectral components which are damped by the transducer prior to transmit. Due to the long duration of coded excitation signals, pulse compression techniques are required for time-of-flight measurements. Common pulse compression filters are discussed and appropriate filtering of the compression waveform is designed to keep the side lobe level acceptably low. An experimental assessment of the presented measurement techniques reveals that the signal conditioning substantially increases the axial resolution. However, a tapered Wiener filter should be used for best trade-off between side lobe level and axial resolution. We used the proposed method to measure different plates of steel, aluminum and polymethylmethacrylate (PMMA) of various thicknesses and the results show very good agreement with the reference values, which we obtained with a micrometer screw and by standard time-of-flight measurement, respectively. The relative error for the plate thickness is smaller than 2.2% and that for speed of sound smaller than 3%. It is remarkable that plate thickness could be measured down to 60% of the wavelength.



FAU-Autoren / FAU-Herausgeber

Fink, Michael
Lehrstuhl für Sensorik
Kiefer, Daniel A.
Lehrstuhl für Sensorik
Rupitsch, Stefan PD Dr.
Lehrstuhl für Sensorik


Zitierweisen

APA:
Kiefer, D.A., Fink, M., & Rupitsch, S. (2017). Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates using Coded Excitation Signals. IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 99. https://dx.doi.org/10.1109/TUFFC.2017.2746900

MLA:
Kiefer, Daniel A., Michael Fink, and Stefan Rupitsch. "Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates using Coded Excitation Signals." IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 99 (2017).

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Zuletzt aktualisiert 2018-18-10 um 00:20