The potential of tunable mechanical vibration absorbers to reduce aircraft interior noise is discussed. First, a simplified analytical model describing the vibrational and acoustic fields for a propeller aircraft is developed. The system then consists of introducing multiple vibration absorbers whose properties can be electronically adjusted, attached to the cylindrical structure representative of the aircraft fuselage. These adaptive absorbers are configured to have resonances on or very close to the disturbance frequency and thus can exert significant reactive force with a low system mass and a very low power consumption. The properties of the absorbers are globally adapted in order to minimize a cost function based upon interior acoustic levels. This ensures that the absorbers minimize the structural cylinder modes well coupled to the interior acoustic field. Previous work has shown that such globally detuned absorbers out perform tuned absorbers in which the base motion is directly minimized. The paper concentrates on further studying the effects of the detuning factor and mechanical impedance as well as the absorbers number and position, on the interior noise attenuation. Two disturbance frequencies, i.e. the first and second propeller blade passage frequency, are investigated. The results show that, for properly configured absorbers, large global attenuation of aircraft interior noise can be achieved and confirm that the detuned absorbers provide more sound attenuation than the tuned.
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