Wind Noise and Motorcycle Crash Helmets
Autor: | J.A. Binnington, A. W. McCombe, D. Nash |
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Rok vydání: | 1994 |
Předmět: |
Engineering
Acoustics and Ultrasonics Acoustics Crash 02 engineering and technology 01 natural sciences 0203 mechanical engineering Wind noise 0103 physical sciences 010301 acoustics Sound (geography) Simulation Civil and Structural Engineering Wind tunnel geography geography.geographical_feature_category business.industry Mechanical Engineering Attenuation Building and Construction Rate of increase Noise 020303 mechanical engineering & transports Geophysics Mechanics of Materials business Acoustic attenuation |
Zdroj: | Journal of Low Frequency Noise, Vibration and Active Control. 13:49-57 |
ISSN: | 2048-4046 1461-3484 |
DOI: | 10.1177/026309239401300202 |
Popis: | An investigation was undertaken into the source and levels of wind noise in motorcycle helmets, and their sound attenuation characteristics. All noise measurements increased in a linear fashion when plotted against log10 speed. Low frequency wind noise displayed a greater rate of increase than vehicle noise and surpassed it and the recommended 8 hour occupational maximum of 90dB(A) at approximately 17m/s (40mph/68kph) to reach levels of 111dB(A) at 44m/s (100mph/170kph). There were no statistical differences in the sound levels for different motorcycles, riding position or helmet fit. There were small but significant differences between helmet types. A wind tunnel analysis indicates a turbulent boundary layer as the sound source. As currently designed, a typical motorcycle crash helmet provides no useful sound attenuation below 2000 Hertz and thus little protection against the damaging effects of wind noise. It is suggested that improvements in helmet attenuation characteristics would go some way to addressing this problem. |
Databáze: | OpenAIRE |
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