Piezoelectric smart structures for noise reduction in a cabin

The feasibility of piezoelectric smart structures for cabin noise problem is studied numerically and experimentally. A rectangular enclosure, one side of which is a plate while the other sides are assumed to be rigid, is considered as a cabin. A disk-shaped piezoelectric sensor and actuator are mounted on the plate structure and the sensor signal is returned to the actuator with a negative gain. An optimal design of the piezoelectric structure for active noise control of the cabin is performed. The design variables are the locations and sizes of the disk-shaped piezoelectric actuator and sensor and the actuator gain. To model the enclosure structure, a finite element method based on a combination of three dimensional piezoelectric, flat shell and transition elements is used. For the interior acoustic medium, the theoretical solution of a rectangular cavity in the absence of any elastic structures is used and the coupling effect is included in the finite element equation. The design optimigation is performed at resonance and off-resonance frequencies, with the results showing a remarkable noise reduction in the cavity. An experimental verification of the optimally designed configuration confirms the feasibility of piezoelectric smart structures in resolving cabin noise problems.