Cabin noise alleviation through fuselage skin embedded smart actuators

This paper deals with an integrated spectral-integral formulation for prediction and active control of noise generated by propellers inside the cabin of a general aviation aircraft. This problem is of great interest in the design of modern turboprop aircraft, where passenger comfort is a primary goal and the application of noise abatement techniques is welcome. It has to be analysed in a multidisciplinary context, in that involves interaction between exterior noise field, elastic fuselage dynamics, interior acoustics and control system. A smart fuselage composed of piezoelectrics elements embedded into the structure skin is supposed to be impinged by the external sound wave generated by the propellers. An optimal harmonic control formulation for the synthesis of a control law driving actuators patches so as to alleviate cabin noise is presented. The aeroacoustoelastic plant model considered in the control problem is obtained by combining a modal approach for the description of the acoustic field within the cabin and the elastic displacement of the smart shell, with a BEM scattering modelling based on the Ffowcs Williams and Hawkings Equation for the prediction of exterior pressure disturbances. Considering a general aviation aircraft fuselage impinged by pressure disturbances emitted by a couple of pulsating point sources moving with it, numerical results examine the effectiveness of the control approach applied for several configurations of actuated piezoelectrics elements.