Constrained-layer damping

About: Constrained-layer damping is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 15758 citations.

Spectral finite-element modeling of the longitudinal wave propagation in rods treated with active constrained layer damping

Abstract: A spectral finite-element model (SFEM) is developed to describe the propagation of longitudinal waves in rods treated with active constrained layer damping (ACLD) treatments. The model is formulated in the frequency domain using dynamic shape functions that capture the exact displacement distributions of the different ACLD layers. In this manner, a small number of elements is needed to accurately model the wave propagation dynamics, particularly in rods with discontinuities and partial ACLD treatments. Numerical examples are presented to illustrate the accuracy of the SFEM as compared to the exact solutions. Application of the SFEM to beams, plates and shells treated with ACLD treatments is a natural extension of the present work.

Vibration control of plates with active constrained-layer damping

Abstract: Bending vibration of flat plates is controlled using patches of active constrained layer damping (ACLD) treatments. Each ACLD patch consists of a visco-elastic damping layer which is sandwiched between two piezo-electric layers. The first layer is directly bonded to the plate to sense its vibration and the second layer acts as an actuator to actively control the shear deformation of the visco-elastic damping layer according to the plate response. With such active/passive control capabilities the energy dissipation mechanism of the visco-elastic layer is enhanced and its damping characteristics of the plate vibration is improved. A finite element model is developed to analyze the dynamics and control of flat plates which are partially treated with multi-patches of ACLD treatments. The model is validated experimentally using an aluminum plate which is 0.05 cm thick, 25.0 cm long, and 12.5 cm wide. The plate is treated with two ACLD patches. Each of which is made of SOUNDCOAT (Dyad 606) visco- elastic layer sandwiched between two layers of AMP/polyvinylidene fluoride (PVDF) piezo- electric films. The piezo-electric axes of the patches are set at zero degrees relative to the plate longitudinal axis to control the bending mode. The effect of the gain of a proportional control action on the system performance is presented. Comparisons between the theoretical predictions and the experimental results suggest the validity of the developed finite element model. Also, comparisons with the performance of conventional passive constrained layer damping clearly demonstrate the merits of the ACLD as an effective means for suppressing the vibration of flat plates.

Performance of Smart Damping Treatment Using Piezoelectric Fiber-Reinforced Composites

Abstract: This study deals with the active constrained layer damping (ACLD) of laminated composite plates to demonstrate the performance of piezoelectric fiber-reinforced composite (PFRC) layer as the constraining layer of ACLD treatment. A finite element model is developed for the smart composite plates integrated with the patches of ACLD treatment. The performance of the constraining PFRC layer has been investigated for active damping of thin symmetric and antisymmetric crossply and antisymmetric angle-ply laminated composite plates. The main concern of this study has been focused on investigating the significant effect of variation of piezoelectric fiber orientation in the PFRC layer on enhancing the damping characteristics of the laminated substrate plates, and the fiber angle in the PFRC layer for which the control authority of the patches becomes maximum has been determined.

Robust control of plate vibration via active constrained layer damping

Abstract: In this paper, the theoretical modeling of a plate partially treated with active constrained layer damping (ACLD) treatments and its vibration control in an H ∞ approach is discussed. Vibration of the flat plate is controlled with patches of ACLD treatments, each consisting of a viscoelastic damping layer which is sandwiched between the piezo-electric constrained layer and the host plate. The piezo-electric constrained layer acts as an actuator to actively control the shear deformation of the viscoelastic damping layer according to the vibration response of the plate excited by external disturbances. In the first part of this paper, the Mindlin–Reissner plate theory is adopted to express the shear deformation characteristics of the viscoelastic damping layer, meanwhile GHM (Golla–Hughes–McTavish) model of viscoelastic damping material and FEM (finite element model) are incorporated to describe the dynamics of the plate partially treated with ACLD treatment. In the second part, particular emphasis is placed on the vibration control of the first four modes of the treated plate using H ∞ robust control method. For this purpose, an H ∞ robust controller is designed to accommodate uncertainties of the ACLD parameters, particularly those of the viscoelastic damping core which arise from the variation of the operation temperature and frequency. Disturbances and measurement noise are rejected in the closed loop by H ∞ robust controller. In the experimental validation, external disturbances of different types are employed to excite the treated plate. The results of the experimental clearly demonstrate that the proposed modeling method is correct and the ACLD treatments are very effective in fast damping out the structural vibration as compared to the conventional passive constrained layer damping (PCLD).