Numerical and Experimental Comparison of the Adaptive Feedforward Control of Vibration of a Beam with Hybrid Active-Passive Damping Treatments

This article concerns the adaptive feedforward control of vibration of a freely supported beam with two distinct surface mounted hybrid active—passive damping treatments. The first configuration concerns the use of an Active Constrained Layer Damping (ACLD) patch alone, where the piezoelectric constraining layer is actively utilized to increase the shear deformation of the sandwiched passive viscoelastic layer and at the same time to apply forces and moments into the structure, which will balance the power flows into the structure, and is denoted by ACLD configuration. The second configuration regards the use, as an active element in the control, of the piezoelectric patch alone, denoted by Active Damping (AD), and since the constraining layer of the ACLD treatment also bonded on the other side of the beam is not actively utilized, a Passive Constrained Layer Damping (PCLD) treatment is utilized in combination with an AD one, yielding an AD/PCLD configuration. A finite element model of the beam with the damping treatments is used for the simulation of the adaptive feedforward controller which is also implemented and tested in real-time. The aims are to compare the predicted and measured damping performances of the two treatments in terms of vibration reduction, control effort, stability and robustness, when a filtered-reference LMS algorithm is used to cancel the effects of a broadband voltage disturbance applied into a third surface mounted piezoelectric patch which is used to excite the beam.