Active skin for noise control

The present work presents the main results of a numerical and experimental activity devoted to an active skin panel design and testing on a laboratory specimen. This applications represent the natural development of those performed at the Department during the last eight years of research activities in the active noise and vibration control field, based upon the use of monolithic piezoelectric patches bonded or embedded within the structure. In this approach one is concerned with sound radiated from the surface of the skin rather than the primary structure. Since the active-skin functions by modifying the radiation impedance, it is not necessary to directly modify the structural vibration and the approach is suitable for massive or stiff structures that have low mobility. First experimental tests showed that an overall 20 dB reduction on emitted noise may be achieved in the whole range below the 500 Hz (for sine or broadband test signal); during these activities also interesting results concerning control algorithms architecture and implementation have been derived, whose results will be herein presented.