Control of vibration from a submerged plate

The active control of sound radiation from a flat rectangular plate with one side subjected to fluid-loading is analytically studied and validated experimentally. The objective of the research is to develop methodology for optimally controlling the vibration and fluid borne sound radiation from a plate by only controlling the vibration frequencies that radiate into the acoustic far field as part of the controller minimizing function. A finite element model is developed to describe the interaction between the dynamics of the plate, fluid, and controller. An adaptive Least Mean Square (LMS) algorithm is implemented in the experiment to attenuate the water borne radiated sound from the vibrating plate by using a piezo-electric patch bonded to the surface of the plate.; An analytical and computational model of the vibration of the plate with piezo-electric actuators was developed based on the finite element approach. The effect of the elastic and inertial properties of the actuators on the stiffness and mass matrices along with the fluid coupling are considered. The rectangular plate is mounted on the top of a water tank with one side of the plate in vacuo while the other side is immersed in water. Two different experiments are conducted to investigate the effectiveness of the piezo-electric actuator in controlling the radiated sound pressure of the fluid-loaded plate. In the first experiment, the water borne radiated sound pressure is taken as the error signal of the Filter-X LMS controller while the second experiment is conducted by using vibration amplitude of the plate as the error signal.; The obtained results show that both control strategies utilizing the Filter-X LMS algorithm are successful at attenuating the radiated water borne sound pressure as well as the vibration amplitude of the plate. Comparing the two control strategies indicates that the required control voltage is identical, but the convergence speed of the adaptive process while using vibration amplitude of the plate as error signal is quicker than while using radiated sound pressure as the error signal.