High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in...

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Main Authors: Mihai Valentin Predoi, Cristian Cătălin Petre, Ovidiu Vasile, Mihail Boiangiu
Format: Article
Language:English
Published: Wiley 2014-01-01
Series:Shock and Vibration
Online Access:http://dx.doi.org/10.1155/2014/105971
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author Mihai Valentin Predoi
Cristian Cătălin Petre
Ovidiu Vasile
Mihail Boiangiu
author_facet Mihai Valentin Predoi
Cristian Cătălin Petre
Ovidiu Vasile
Mihail Boiangiu
author_sort Mihai Valentin Predoi
collection DOAJ
description Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.
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series Shock and Vibration
spelling doaj-art-45ec0ad3ff5b4f1ba6c8a67b932ab3932025-08-20T02:39:19ZengWileyShock and Vibration1070-96221875-92032014-01-01201410.1155/2014/105971105971High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic TransducerMihai Valentin Predoi0Cristian Cătălin Petre1Ovidiu Vasile2Mihail Boiangiu3Department of Mechanics, Polytechnic University of Bucharest, Splaiul Independenţei 313, 60048 Bucharest, RomaniaDepartment of Strength of Materials, University Politehnica of Bucharest, Splaiul Independenţei 313, 60048 Bucharest, RomaniaDepartment of Mechanics, Polytechnic University of Bucharest, Splaiul Independenţei 313, 60048 Bucharest, RomaniaDepartment of Mechanics, Polytechnic University of Bucharest, Splaiul Independenţei 313, 60048 Bucharest, RomaniaUltrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.http://dx.doi.org/10.1155/2014/105971
spellingShingle Mihai Valentin Predoi
Cristian Cătălin Petre
Ovidiu Vasile
Mihail Boiangiu
High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
Shock and Vibration
title High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
title_full High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
title_fullStr High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
title_full_unstemmed High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
title_short High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer
title_sort high frequency longitudinal damped vibrations of a cylindrical ultrasonic transducer
url http://dx.doi.org/10.1155/2014/105971
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