Wide-band transmission noise reduction of smart panels featuring piezoelectric shunt circuits and sound absorbing material

초록

The possibility of a wide-band noise reduction of piezoelectric smart panels is experimentally studied. Piezoelectric smart panel is basically a plate structure on which piezoelectric devices with shunt electronics are mounted and sound absorbing material is bonded on the surface of the structure. Sound absorbing material can absorb the sound transmitted at mid frequency effectively while the use of piezoelectric shunt circuits can reduce the transmission at resonance frequencies of the panel structure. Piezoelectric shunting circuit, composed of register and inductor, are determined based on maximizing the dissipated energy through the circuit. To be able to reduce the sound transmission at low panel resonances, multi-mode damping with one piezoelectric device is essential and it is achieved by using the measured electrical impedance model. The noise reduction performance of the panels is tested on an acoustic tunnel. The tunnel is made of a guided tunnel that has a square cross section and loud speaker is used as a sound source. Panels are mounted in the middle of the tunnel and the transmitted sound pressures across panels are measured. Several panels according to different absorbing material thickness, combination of double panels and location of piezoelectric devices are tested.