Hybrid active-passive constrained layer damping treatments in beams, plates and shells

Abstract

The basic concept of Hybrid Active-Passive Constrained Layer Damping (HAPCLD) treatment was proposed by introducing active control to the concept of passive constrained layer damping configuration in the 1990s to compensate for weak points in active and passive controls by using their respective merits for more robust and stable control. Since then, combinations of various configurations and applicable control strategies have been proposed and studied in many engineering areas. However, there is still a need for a new modelling method to more easily establish models of HAPCLD treatment and its validation through control analysis and experiment with various structures from beams to curved plates.

In this thesis, velocity feedback control strategy was applied to cantilever beams with four different configurations of HAPCLD treatment to check their applicability. Moreover, the application was expanded to flat and curved plates. Control results with each configuration for flat and curved plates were analysed by using self-established MATLAB codes based on the Finite Element Method (FEM) with the basic concept of a layer-wise approach for coupling each layer of structures and deriving Equivalent Single Layer (ESL) models. This new numerical modelling method was established by introducing coupling matrices based on a layer-wise approach to combine individual FE mass and stiffness matrices of each layer into one ESL model for a whole structure. Furthermore, these numerical models were supported by experiments in a lab. All measured data was compared with simulation results and they were confirmed in good agreement in general. In addition to this, the relation between mode shapes and control by piezoelectric patches occupying a broader area than an ideal actuator was studied to find the conditions for more stable control of flat and curved plates.

In conclusion, as discussed for active control with beams, AC/PSOLD treatment, which consists of a piezoelectric actuator directly attached to a base structure and a stand-off layer with a viscoelastic core and elastic constraining patch laminated on the piezoelectric actuator, was clarified to give the most efficient and robust active control results for plates regardless of the curvature of all HAPCLD treatments dealt within this thesis as well. AC/PSOLD treatment could give similar reductions with smaller control gain in simulation. And, larger reductions were obtained with measured transfer functions in experiments than other configurations.

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Identifiers

ORCID for Emiliano Rustighi: orcid.org/0000-0001-9871-7795

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