Active vibration control in finite plates using a structural power flow approach

This paper proposes a strategy for the active control of flexural vibration in plates. The proposed strategy consists of minimizing the power flow across a closed path encircling the perturbation and the control actuators. This approach is equivalent to active noise control based on the far-field power over a closed volume, where the disturbance source location is assumed to be known. A frequency-domain adaptive control scheme has been developed aiming at the attenuation of steady-state, periodic vibrations. It is assumed that the location of the perturbation is known. The proposed strategy is investigated using a numerically simulated example consisting of a rectangular plate excited by a perturbation force. Some of the main issues concerning the implementation of a frequency-domain adaptive controller are investigated. The expression of the gradient of the power flowing in or out of a region encircling the perturbation force and the control actuators is derived. The convergence properties of the adaptive scheme are investigated using an off-line simulation in the frequency domain. It is shown that the power flow control can result in significant vibration reduction, which is the ultimate goal.