Vibration control of rotating beams with active constrained layer damping

The vibrations of rotating beams are attenuated using an active constrained layer damping treatment. The treatment consists of a visco-elastic damping layer which is sandwiched between two piezo-electric layers. The resulting three-layer composite when bonded to the beam acts as a 'smart' constraining layer damping treatment with built-in sensing and actuation capabilities. With such capabilities the shear deformation of the visco-elastic damping layer can be controlled and actively tuned to the response of the rotating beam in order to enhance the energy dissipation mechanism and improve the vibration damping characteristics. The dynamics of a rotating beam, treated fully or partially with the active treatment, are described with a finite-element model. The model accounts for the interaction between the rotating beam, the piezo-electric sensor/actuator, the visco-elastic damping layer and an appropriate control law. The model provides means for predicting the damping characteristics of the active treatment at different setting angles and controller gains. The theoretical predictions of the model are compared with the experimental performance of a beam partially treated with a Dyad 606 visco-elastic layer sandwiched between two layers of polyvinylidene fluoride piezo-electric films. Comparisons are also presented with the performance of conventional passive constrained layer damping. The results obtained clearly demonstrate the attenuation capabilities of actively controlled constrained layer damping and suggest its potential in suppressing the vibration of practical systems such as helicopter rotor blades.