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.

Active constrained layer damping of geometrically nonlinear transient vibrations of composite plates using piezoelectric fiber-reinforced composite

Abstract: This paper addresses the analysis of active constrained layer damping (ACLD) of geometrically nonlinear transient vibrations of laminated thin composite plates using piezoelectric fiber-reinforced composite (PFRC) materials. The constraining layer of the ACLD treatment is considered to be made of the PFRC materials. The Golla–Hughes–McTavish (GHM) method has been used to model the constrained viscoelastic layer of the ACLD treatment in the time domain. A finite element model has been developed for the cross-ply and antisymmetric angle-ply plates integrated with the patches of ACLD treatment undergoing geometrically nonlinear vibrations. The Von Ka`rma`n-type nonlinear strain displacement relations and the first-order shear deformation theory (FSDT) are used for deriving this coupled electromechanical nonlinear finite element model. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of the cross-ply and antisymmetric angle-ply plates for suppressing the geometrically nonlinear transient vibrations of the plates. Emphasis has also been placed on investigating the effect of variation of fiber orientation in the PFRC material on the control authority of the ACLD patches.

Vibration control of rotating beams with active constrained layer damping

Abstract: 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.

Modelling of a Hybrid Constrained Layer/Piezoceramic Approach to Active Damping

Abstract: It has been shown that significant reductions in structural vibration levels can be achieved using a hybrid system involving constrained layer damping and active control with piezoceramics. In this paper, mathematical models based on the Rayleigh Ritz approach, are developed to describe the longitudinal and flexural vibration behaviour of a cantilevered beam when excited using piezoceramic patches bonded to a constrained layer damping treatment. Predictions of static and steady state dynamic behaviour, obtained using the models are validated by comparison with results from finite element analysis and laboratory experiments. The models are then used in open loop and closed loop velocity feedback control simulations to demonstrate the improvements in stability and performance achieved using this method over that achieved using conventional active control.

Nonlinear vibration analysis of fiber reinforced composite cylindrical shells with partial constrained layer damping treatment

Abstract: This research proposes a novel analytical model capable of accurately predicting the strain-dependent characteristics of fiber reinforced composite shells (FRCSs) with partial constrained layer damping (CLD) treatment by considering the nonlinearities of fiber reinforced composite and viscoelastic materials simultaneously. The nonlinear material properties are represented based on Jones-Nelson nonlinear theory, energy-based strain energy method, and complex modulus method. Then, the governing equations of motion for FRCSs are developed via Ritz method, and the identification procedure of nonlinear fitting parameters is also presented. By taking a T300 carbon fiber/epoxy resin cylindrical shell with partial CLD patches as an example, a series of experiments are carried out to validate the proposed modeling approach. Finally, the effects of material properties on nonlinear vibration behaviors of FRCSs covered with partial CLD patches are evaluated. Comparisons show that the proposed nonlinear model is more accuracy than that without considering strain dependence, where the maximum errors between the proposed model and measured data for natural frequencies, damping ratios and resonant response are 6.9%, 11.3%, and 11.2%, respectively.

Novel epoxy compositions for vibration damping applications

Abstract: Three epoxy compositions have been developed by using polyether amine hardeners having varying chain lengths of polyethers. Unlike normal epoxies, the compositions show low glass transition temperatures (0-45°C). Dynamic mechanical analysis and time-temperature superposition of the isotherms indicate that they have broad and high loss factor values over broad frequency and temperature ranges suggesting their application as viscoelastic materials in constrained layer damping of structural vibrations.