Numerical Analysis on Vibro-acoustic Characterisation of Hybrid Honeycomb Structure with Flow Permeability

Abstract

The application of conventional noise attenuating structures was often limited when the exchange of air was required due to the trade-off between their noise attenuation properties and ventilation efficiency. The large physical footprint of conventional noise attenuating structures with flow permeability had also limited their applications. This paper investigated the use of corrugation structure in lightweight honeycomb sandwich panels with flow permeability to improve noise attenuation while preserving ventilation. The vibro-acoustic property of the honeycomb structure with flow permeability at low to medium frequency range (50-3000 Hz) was investigated through numerical simulation. Two different hybrid panel designs with U-shaped and V-shaped corrugations in the honeycomb core had been proposed and were found to exhibit superior sound transmission loss (STL) compared to the honeycomb panel without significantly affecting the flow performance. It was found that in the frequency range of 50-3000 Hz, the unweighted STL of the U-shaped corrugation honeycomb hybrid panel (UCHP) and V-shaped corrugation honeycomb hybrid panel (VCHP) was 19 dB and 25 dB higher than the honeycomb panel respectively with negligible effect on the flow performance. The proposed hybrid panel showed promising noise attenuation applications which involved fluid flows such as in fan and engine noise reduction.