Vibroacoustic soundproofing for helicopter interior

Abstract

As VIP passengers generally want to fly civil and executive jets where vibratory and acoustic environment is smoother than on the normal jets. Helicopter interior noise is generated by main and tail rotors, engines, main gearbox, and aerodynamic turbulence (Lu et al., 2018). Because of these sources, the tonal and broadband noise is incredibly high and needs to be reduced. Conventional passive system (soundproofing) is the best way to control the acoustic of the cabin whereas active systems (active vibration and noise control) are not completely reliable or applicable. The design of the soundproofing may be researched by simulation using one of these programs: ANSYS, SOLIDWORKS 2020 and ACOUSTIC analysis Vibroacoustic Monitoring (VAM) approach. The analyses were performed from frequency ranges, 5-10Hz and 0-2000Hz then transformed into frequency velocity domain using Proudman’s equations (Lu et al., 2017). Soundproofed ANSYS models are validated using instantaneous sound pressure levels measured within the helicopter during flight. The acoustic detection method for GAZELLE is also performed successfully in SOLIDWORKS for aluminum alloy and titanium alloy, this proves the relationship between acoustic power levels and material configuration. The noise coefficient responses of interior materials are used as main index for soundproofing helicopter interiors. The results of this research can be used for implementation of VAM approach for soundproofing helicopter interiors.

Keywords

• vibro-acoustic
• soundproofing
• sound pressure level
• VAM approach
• DAVA approach
• sound absorption coefficient material