ACOUSTIC CONTROL USING A SELF-SENSING ACTUATOR

An analytical and experimental demonstration of a self-sensing actuato r that is used actively to control sound transmission/radiation throug h a vibrating plate is presented in this paper. Self-sensing is a nove l application of piezomaterials, in which the same piece of piezomater ial is used as both a sensor and actuator. A plane acoustic wave incid ent on a clamped, thin circular plate was used as a noise source, and a self-sensing actuator bonded to the plate was used to control and se nse vibration of the plate. The sound transmission reduction problem w as approached as a structural vibration control problem that minimizes the velocity of the plate since the far-field sound pressure is relat ed to the vibrating velocity of the structure. The results show that t he first structural vibration mode is well controlled with a reduction of at least 78 percent in the displacement and velocity of the plate. This corresponds to a 13 dB reduction in the acoustic response. These results indicate that it self-sensing actuator bonded to the plate ca n be employed to attenuate the sound transmitted or radiated from the plate. (C) 1995 Academic Press Limited