Ein Beitrag zur Auslegung von Ultraschallwandlern für Abstandsmessungen
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Date
2002-10-24
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Universität Dortmund
Abstract
Das Frequenz- und Abstrahlverhalten von Ultraschallwandlern beeinflusst den Einsatz und die Ansteuerung der Systeme für die Abstandsmessung. Verlässliche Aussagen über ihr Verhalten werden durch eine umfassende, realitätsnahe und verifizierte Simulation der Ultraschallwandler ermöglicht. Wesentlicher Bestandteil der Simulation ist die Anwendung der Finite-Elemente-Methode, die durch weitere Berechnungsverfahren unterstützt wird. Die modular aufgebaute Simulationsrech-nung besteht aus den Phasen Spektrogramm-, Verschiebungsprofil- und Schallfeldberechnung. Die Schalldruckverteilung im Fernfeld und deren Druckmaxima in Abhängigkeit von der Frequenz werden mithilfe der Näherungslösung nach dem Huygen-Fresnelschen-Integral berechnet. Die Verifikation der Teilergebnisse wird durch die experimentellen Untersuchungen Schallpegelmessung, Laserinterferometrie und Schallfeldmessung möglich. Die Da-tenbasis wird durch bereits publizierte Kennwerte sowie durch Experimente mit selbst gefertigten Ultraschallwandlern ergänzt. Die ersten Vergleiche der Ergebnisse aus Simulation und Experiment weisen in eine erfolgversprechende Richtung. In der Weiterführung dieser Arbeit wäre eine anwendungsspezifische, kurzfristige und preisgünstige Wandlerherstellung denkbar, bei der Dank zuverlässiger Simula-tionsergebnisse auf umfangreiche experimentelle Untersuchungen verzichtet werden könnte.
The frequency and radiation behaviour of ultrasonic transducers affects the employment and the control of the systems for the distance measurement. Reliable statements about their behaviour are made possible by a comprehensive, close-to-reality and verified simulation of the ultrasonic transducers. A substantial component of the simulation is the application of the finite element method, which is supported by further computation methods. The modularly designed simulation calculation consists of the following phases: spectrogram, displacement field, sound field computation. The sound pressure distribution in the far field and their pressure maxima as a function of the frequency are calculated by means of the approximation solution after the Huygen Fresnel integral. The verification of the partial results is made possible by the experimental investigations of sound level measurement, laser interferometry and sound field measurement. The database is supplemented by characteristic values already published as well as by experiments with self-manufactured ultrasonic transducers. The first comparisons of the results of simulation and experiment are promising. In the continuation of this work a user-specific, short-term and low-priced transducer production might be conceivable even without extensive experimental investigations thanks to reliable simulation results.
The frequency and radiation behaviour of ultrasonic transducers affects the employment and the control of the systems for the distance measurement. Reliable statements about their behaviour are made possible by a comprehensive, close-to-reality and verified simulation of the ultrasonic transducers. A substantial component of the simulation is the application of the finite element method, which is supported by further computation methods. The modularly designed simulation calculation consists of the following phases: spectrogram, displacement field, sound field computation. The sound pressure distribution in the far field and their pressure maxima as a function of the frequency are calculated by means of the approximation solution after the Huygen Fresnel integral. The verification of the partial results is made possible by the experimental investigations of sound level measurement, laser interferometry and sound field measurement. The database is supplemented by characteristic values already published as well as by experiments with self-manufactured ultrasonic transducers. The first comparisons of the results of simulation and experiment are promising. In the continuation of this work a user-specific, short-term and low-priced transducer production might be conceivable even without extensive experimental investigations thanks to reliable simulation results.
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Keywords
Abstandsmessung, Abstrahlverhalten, Fernfeld, Finite-Elemente-Methode, Frequenzverhalten, Laserinterferometrie, Schalldruckverteilung, Schallfeldberechnug, Simulation, Ultraschallwandler, distance measurement, radiation behavior, far field, finite element method, dynamic response, laser interferometry, sound pressure distribution, sound pressure calculation, Simulation, Ultrasonic transducer