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Air-coupled UT transducers

 
: Gebhardt, W.

Czech Society for Nondestructive Testing; Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. -DGZfP-, Berlin:
NDT in Progress : Meeting of NDT-Experts; June 20 - 22, 2001, Castle Trest', Czech Republic ; proceedings
Prag, 2001
ISBN: 80-238-7263-X
pp.95-105
NDT in Progress, Meeting of NDT-Experts <2001, Prag>
English
Conference Paper
Fraunhofer IZFP ()
luftgekoppelter Ultraschall; air-coupled ultrasound; piezoelektrischer Verbundwerkstoff; piezoelectric composite material

Abstract
Based upon piezoelectric composite materials, air borne ultrasonic probes with frequencies above 100 kHz were developed. These probes are characterized by a bandwidth larger than 50 % as well as a signal-to noise ratio higher than 100 dB. The essential part of the probes is a piezo-composite (1-3-configuration) developed at the IZFP. The piezo-composites are characterized by a high electroacoustic coupling coefficient (about 0.7), better aoustic matching to gas (acoustic impedance 6 to 10 MRayl in comparison to 35 MRayl of the piezo-ceramic) and a low mechanical quality factor. To further improve the efficiency of air coupled probes compressed air shoes and travelling wave transducers are in current development.

: http://publica.fraunhofer.de/documents/N-5698.html