Global attenuation of random vibrations in a tapered and swept panel

The thin panels used in many modern-day structures are often prone to vibrate at excessive amplitudes. Instead of suffering the weight penalties which may be associated with passive damping treatments, an approach which can make use of the computational power on board many of these structures is to dampen such vibrations actively. Piezoceramic strain actuators, because of their compact and lightweight nature, and because of their lack of a need for a supporting structure to provide reaction points, are ideally suited for such applications. A technique is presented herein for the design and implementation of two two-input-three-output multi-variable controllers which use two piezoceramic patches as actuators, and a further two such patches, as well as an accelerometer, as sensors. These controllers are implemented on a tapered and swept aluminium panel subject to random excitation, such that the first five modes are simultaneously observed and controlled. A technique that determines good locations for the sensors and actuators, based on the modes to be controlled, is employed. The results show that the controllers perform well with respect to spillover, robustness and non-linearities. Finally, the results of an accelerometer traverse are presented, demonstrating the global nature of the vibration attenuation achieved. (C) 1997 Commonwealth of Australia.