Design of an Adaptive Dynamic Vibration Absorber for acoustic levels reduction of a regional aircraft passengers'cabin

This study concerns a design procedure for the definition of an ADVA aimed at reducing the interior acoustic field within a regional propeller aircraft. At low frequency, sound excitation is dominated by the Blade Passage Frequency (BPF) and its harmonics. Because in that range the structural acoustic coupling is significant, it is reasonable that a structural device can absorb acoustic energy. As well-know, tones are very critical for passengers' well-being and comfort. DVA are simple and effective devices for extracting energy from the structure. Providing them with some adaptive potentiality may further improve their performance levels. Adaptive DVA could be used for following the small variations occurring in the BPF during cruise (around 2%), to modify the device characteristics for different regimes of the propeller to tune the absorption peak at the optimal frequency. Moving from previous analyses, the author develop the assessed procedure to take into account the peculiarity of a fuselage of a turboprop aircraft, and define size, material, number and position of the selected system. After a parametric study to identify DVA optimal mass and stiffness, its geometrical layout is defined and an architecture to give it adaptive property thank to SMA system.