ACTIVE CONTROL OF SOUND-TRANSMISSION THROUGH ELASTIC PLATES USING PIEZOELECTRIC ACTUATORS

A theoretical investigation is undertaken concerning the potential of actively controlling sound transmission/radiation from a vibrating plate using piezoelectric elements bonded to the plate surface as actuators. The system analyzed consists of a plane acoustic wave incident on a baffled, clamped, thin circular plate. Sound transmitted through the plate is considered to be the noise field. An approximate theory is used to evaluate the degree of attenuation achieved when sinusoidally activated piezoelectric elements bonded to the panel are used to minimize the total radiated acoustic power. The results show that global attenuation of radiated sound can be achieved on or off plate resonance frequencies. Both the size and the location of the actuator are demonstrated to affect the degree of control achieved and spillover into residual modes. These results, combined with size, compactness, and cost aspects, reveal that piezoelectric elements have great potential in controlling structurally radiated sound.