Previous research has shown that the sound radiated by a vibrating panel can be reduced considerably by the application of tube resonators. In this paper, the influence of tube resonators on sound transmission through a panel is examined. Sound transmission loss measurements demonstrated that by applying tube resonators, the sound transmission loss of panels can be improved compared with the mass law. This was shown for two different configurations: panels with tubes and sandwich panels. A maximum increase in transmission loss of 9.2 dB was obtained for the perforated HC sandwich panel and of 7.1 dB for the panel with tubes. In the entire frequency range above the 500 Hz 1/3OB (one-third Octave Band), the transmission loss of the perforated HC sandwich panel was larger than the mass law. However, for all panels, the increases were not as large as predicted by the one-dimensional analytical models presented in this paper. Moreover, the tube panels showed large decreases in transmission loss in the higher frequency ranges. The predictions for the perforated HC sandwich panels were a little better. To give a better prediction of the transmission loss that can be obtained by panels with acoustic resonators, more detailed models are required. Possible causes for the discrepancies between the measurements and the results obtained with the one-dimensional models are the negative effects of: the flexibility of the panel, the flexibility of the resonators, acoustic coupling between the resonators, random incident sound, coincidence, and boundedness of the panel. Further research is needed and ongoing to study these effects.
Improvement of the sound transmission loss of panels by means of acoustically tuned resonators
Verbesserte Lärmminderung bei Schalenstrukturen durch akustisch abgestimmte Resonatoren
2006
10 Seiten, 14 Bilder, 1 Tabelle, 8 Quellen
Aufsatz (Konferenz)
Englisch
Flugzeugbau , Leichtbauweise , Schallabstrahlung , Schwingungsanregung , Akustik , Schallübertragung , Schallmessung , Resonator , mathematisches Modell , Validierung , experimentelle Untersuchung , Versuchsaufbau , Schale (Träger) , ISO (International Organization for Standardization) , reflektierende Schicht , Helmholtz-Gleichung , Schallstärke , Frequenzbereich , Hallraum , Schallquelle , Eigenfrequenz , Sandwich-Bauweise
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