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Prediction of helicopter cabin noise using statistical energy analysis (SEA)

1986; Acoustical Society of America; Volume: 79; Issue: S1 Linguagem: Inglês

10.1121/1.2023078

1520-9024

James A. Moore,

Aerodynamics and Acoustics in Jet Flows

The noise environment in the cabin of small 6–13 passenger commercial helicopters is dominated by mesh tones generated within the gearbox. Helicopter airframes are efficiently designed to support mechanical loads which results in their also being efficient transmitters of vibratory energy. Structural components of the airframe are characterized by many resonant vibratory modes at higher frequencies in the audio range. Statistical energy analysis (SEA) has proved to be a very useful tool in the development of a model of airframe vibration transmission and coupling to the acoustic environment in the cabin. Under contract support from NASA, Langley, an SEA model of the Sikorsky Aircraft S-76 helicopter was developed and implemented using the Cambridge Collaborative's general purpose SEAM computer code. Characterizations of the structural connections between frame members, and frame members and adjacent skin panels, were developed in implementing the model. Additional coupling loss factors between panels, frames, and acoustics spaces are needed in building the SEA model: Measurements on actual airframes with shaker excitation during flight operating conditions were performed with good agreement between measured and predicted vibration and cabin noise levels.