Noise reduction performance of smart panels incorporating piezoelectric shunt damping

Performance test for transmitted noise reduction of smart panels is experimentally studied. Smart panel is a panel that is utilized a passive material at high frequencies and piezoelectric shunt damping at low frequencies. A multi-mode shunt damping is investigated by using the tuning method based on measured electrical impedance. Three configurations of smart panels are tested: single panel, single panel with sound absorbing material and double panel. The single panel consists of a host plate structure on which four piezoelectric patches are bonded and electrical shunt circuits are connected independently. The parameters for resonant shunt are determined by maximizing the dissipated energy through the circuit. The transmitted noise reduction performance of smart panels is tested in an acoustic tunnel. Sound absorbing material and air gap reduces the sound transmitted at the mid-frequency region effectively while the use of piezoelectric shunt damping can work at resonance frequencies of the panel structure. As a result, a remarkable noise reduction of 15dB was achieved in a wide band frequency region. The double panel exhibits better noise reduction than other panels. This approach was also applied to the structural acoustic problem of turbulent boundary layer (TBL) induced sound radiated from a panel, and results are discussed.