Hybrid Vibration Control Systems

The progress in active constrained-layer damping (ACLD) that has been made over the past years is presented in this paper. These systems are also called hybrid systems. ACLD treatments combine the best features of passive and active control of structural vibrations. Well-established techniques for passive control of structural vibrations and noise are described. A concise discussion of the development of so-called ‘smart’ actuators and sensors and the emergence of suitable control algorithms show how passive techniques were extended to produce ACLD. It is shown how the passive and active components of ACLD complement each other to enable control of both high and low frequency modes of vibration. The active elements allow structures to adapt to suit a changing environment while the passive elements provide a fail-safe mechanism. Because of the available technology, these benefits are available without significant penalties in terms of cost, weight and complexity.