Broadband noise reduction of piezoelectric smart panel featuring negative-capacitive-converter shunt circuit

A broadband noise reduction of a piezoelectric smart panel featuring a negative capacitance converter (NCC) shunt circuit is experimentally investigated. Piezoelectric shunt damping utilized on the panel structure is attractive for noise reduction especially at low resonance frequencies of the structure. To achieve a broadband noise reduction, however, a multimode shunt is necessary. The NCC circuit can be an ideal broadband shunt circuit by nullifying the capacitance of the piezoelectric patch with the circuit. Since the intrinsic capacitance of the patch is not constant with the frequency, the broadband shunt performance of the NCC can be deteriorated. Thus, we introduce the dual-patch NCC circuit on the smart panel. The proposed concept is explained and the tuning and implementation procedures are addressed. The noise reduction performance of the panel is tested in terms of transmission loss according to the standard transmitted noise measurement. The broadband damping performance of the smart panel featuring a dual-patch NCC shunt is compared with the panels featuring resonant shunt circuit and ordinary NCC shunt circuit in terms of acceleration and noise transmission loss. It is found that the dual-patch NCC shunt is more efficient than ordinary NCC and resonant shunt for achieving broadband noise reduction with smart panels.