Vibration control of sandwich plates with active constraining layer damping

The bending and torsional vibration of a new class of composite sandwiched plates are controlled using built-in Active Constrained Layer Damping (ACLD). The ACLD consists of two viscoelastic layers, two piezoelectric layers and one exterior layer. The first viscoelastic layer is sandwiched between the two piezoelectric layers while second viscoelastic layer is contained between the second piezoelectric layer and the exterior layer. The first piezoelectric layer acts as a sensor which is directly bonded to the base plate to sense its vibration and second piezoelectric layer acts as an actuator which induces shear deformation in the two viscoelastic layers in response to the structural vibratron in order to enhance a damping effectiveness.; A finite element model with new displacements fields is developed to model the dynamics and controlled vibration of the composite sandwiched plate/ACLD. Numerical results are presented to demonstrate the performance capabilities of the composite sandwiched plate system. The predictions of this model are validated experimentally and are found to be in close agreement with the experiments. The experimental results indicate that the activation of the ACLD treatment has resulted in increasing the modal damping loss factors as compare to those of the inactivated ACLD (i.e., the PCLD(Passive Constrained Layer Damping)). Also, separate control of the bending and torsional modes of vibration has been demonstrated successfully. Therefore, the proposed sandwiched plate/ACLD system has the potential of being the basic building block of structures where effective vibration damping is essential to their successful operation.