Experimental Investigation on the Sound Reduction Performance of Frequency Controlled Acoustic Interference Cavities
Abstract
The European directives on noise reduction associated with rail, road and aviation clearly depicts the need for high efficiency sound attenuating structures for targeted noise reduction. Consequently, this paper presents key observations from Phase 1 of the UK Department of Transport (DfT) funded research project to investigate the targeted creation of acoustic interference to develop high-efficiency noise abatement structures. Geometrical cavity inspired from existing theories around Herschel-Quincke concept is experimentally investigated for the creation of frequency dependent acoustic interference. The interference cavity within a global structure was digitally conceived and prototyped using the Selective Laser Sintering (SLS) process in a Nylon 12 material. A modified impedance tube method was then used to measure the frequency dependent Sound Reduction Index (R) for a frequency range of 250 to 1600 Hz. The results showed that depending on the frequency of interest acoustic interference can be recreated by controlling the cavity length. In addition R values of 72.47 dB were observed at 900 Hz confirming the potential of the technology for high efficiency noise barriers. The observation presented in this paper establishes a new viewpoint for the use of acoustic interference for targeted noise abatement.Publisher
German Acoustical Society (DEGA)Journal
INTER-NOISE 2016 (ISSN 0105-175x)Additional Links
http://www.internoise2016.org/Type
Conference contributionLanguage
enISSN
0105-175xISBN
9783939296119Sponsors
UK Department of Transport (Transport-Technology, Research and Innovation Grant)Collections
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