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Active vibration control of a cylindrical shell using piezoelectric disks is studied both theoretically and experimentally in this paper. Hamilton's principle is used for deriving dynamic motion equations of the cylinder coupled with piezoelectric disks. The equations are discretised by Rayleigh-Ritz method. An adaptive feedforward controller based on steepest descent method is implemented on a PC to control the modal vibration. The proposed method solves the drawback of using PCs that is sending and receiving data in block form. It is shown that the proposed control system which consists of piezoelectric disks and an adaptive controller is effective in reducing vibration and radiated acoustic noise.

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This paper investigates the active structural acoustic control of sound radiated from a smart cylindrical shell. The cylinder is equipped with piezoelectric sensors and actuators to estimate and control the sound pressure that radiates from the smart shell. This estimated pressure is referred to as a virtual microphone, and it can be used in control systems instead of actual microphones to attenuate noise due to structural vibrations. To this end, the dynamic model for the smart cylinder is derived using the extended Hamilton's principle, the Sanders shell theory and the assumed mode method. The simplified Kirchhoff-Helmholtz integral estimates the farfield sound pressure radiating from the baffled cylindrical shell. A modified higher harmonic controller that can cope with a harmonic disturbance is designed and experimentally evaluated. The experimental tests were carried out on a baffled cylindrical aluminum shell in an anechoic chamber. The frequency response for the theoretical virtual microphone and the experimental actual microphone are in good agreement with each other, and the results show the effectiveness of the designed virtual microphone and controller in attenuating the radiated sound.