Analysis and measurement of a matched volume velocity sensor and uniform force actuator for active structural acoustic control

This paper presents a theoretical and experimental study of the frequency response function of a matched volume velocity sensor and uniform force actuator for active structural acoustic control. The paper first reviews the design of a volume velocity sensor and uniform force actuator on a panel, using piezoelectric film with quadratic shaping of the electrodes. The frequency response function of a matched volume velocity sensor and uniform force actuator bonded on either sides of a panel is then studied in detail. This analysis shows that below 100 Hz the sensor-actuator response is controlled by the bending vibration of the panel and a good estimate of the volumetric component of the transverse vibration of the panel is achieved. At higher frequencies, however, the sensor-actuator response is controlled by the in-plane longitudinal and shear vibration of the panel, which causes the real part of the frequency response function to be not strictly positive and to be characterized by large amplitudes at higher frequencies. These two phenomena are important since they limit the possibility of implementing a stable direct velocity feedback control system using these transducers. (C) 2001 Acoustical Society of America.