Vibration control of rotating beams with active constrained layerdamping

Abstract

The vibrations of rotating beams are attenuated using an activeconstrained layer damping treatment. The treatment consists of a visco-elasticdamping layer which is sandwiched between two piezo-electric layers. Theresulting three-layer composite when bonded to the beam acts as a `smart'constraining layer damping treatment with built-in sensing and actuationcapabilities. With such capabilities the shear deformation of thevisco-elastic damping layer can be controlled and actively tuned to theresponse of the rotating beam in order to enhance the energy dissipationmechanism and improve the vibration damping characteristics.The dynamics of a rotating beam, treated fully or partially with the activetreatment, are described with a finite-element model. The model accounts forthe interaction between the rotating beam, the piezo-electric sensor/actuator,the visco-elastic damping layer and an appropriate control law. The modelprovides means for predicting the damping characteristics of the activetreatment at different setting angles and controller gains. The theoreticalpredictions of the model are compared with the experimental performance of abeam partially treated with a Dyad 606 visco-elastic layer sandwiched betweentwo layers of polyvinylidene fluoride piezo-electric films. Comparisons arealso presented with the performance of conventional passive constrained layerdamping. The results obtained clearly demonstrate the attenuation capabilitiesof actively controlled constrained layer damping and suggest its potential insuppressing the vibration of practical systems such as helicopter rotorblades.