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.

Smart damping of laminated fuzzy fiber reinforced composite shells using 1–3 piezoelectric composites

Abstract: This paper deals with the investigation of active constrained layer damping (ACLD) of smart laminated continuous fuzzy fiber reinforced composite (FFRC) shells. The distinct constructional feature of a novel FFRC is that the uniformly spaced short carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of the continuous carbon fiber reinforcements. The constraining layer of the ACLD treatment is considered to be made of vertically/obliquely reinforced 1‐3 piezoelectric composite materials. A finite element (FE) model is developed for the laminated FFRC shells integrated with the two patches of the ACLD treatment to investigate the damping characteristics of the laminated FFRC shells. The effect of variation of the orientation angle of the piezoelectric fibers on the damping characteristics of the laminated FFRC shells has been studied when the piezoelectric fibers are coplanar with either of the two mutually orthogonal vertical planes of the piezoelectric composite layer. It is revealed that radial growth of CNTs on the circumferential surfaces of the carbon fibers enhances the attenuation of the amplitude of vibrations and the natural frequencies of the laminated FFRC shells over those of laminated base composite shells without CNTs. (Some figures may appear in colour only in the online journal)

Vibration control of beams with active constrained layer damping

Abstract: An analytical methodology is presented to study the active vibration control of beams treated with active constrained layer damping (ACLD). This analytical method is based on the conventional theory of structural dynamics. The process of deriving equations is precise and easy to understand. Hamilton's principle with the Rayleigh–Ritz method is used to derive the equation of motion of the beam/ACLD system. By applying an appropriate external control voltage to activate the piezoelectric constraining layer, a negative velocity feedback control strategy is employed to obtain the active damping and effective vibration control. From the numerical results it is seen that the damping performances of the beam can be significantly improved by the ACLD treatment. With the increase of the control gain, the active damping characteristics are also increased. By equally dividing one ACLD patch into two and properly distributing them on the beam, one can obtain better active vibration control results than for the beam with one ACLD patch. The analytical method presented in this paper can be effectively extended to other kinds of structures.

Constrained Damping Layer Treatments: Finite Element Modeling

Abstract: In this paper we assess the performance of finite element models in modeling structures with sheer damping treatments. We analyze the finite element modeling of constrained layer damping (CLD) and integrated layer damping (ILD) treatments using viscoelastic materials, devoting special attention to the spatial modeling of the treatment and to the characterization of the viscoelastic material properties. In this work, we used a finite element commercial software (MSC.Nastran) to simulate the dynamic response of aluminum plates with both treatment configurations (CLD and ILD). The spatial modeling of the treatment was devel-oped using three different models, all based on a layered assembly of plate/brick conventional finite elements. The dynamic properties of the viscoelastic material were taken into account in the numerical simulation using the complex modulus approach. The numerical results are correlated with experimental data obtained for four treated specimens by direct comparison of the frequency respo...

Performance Characteristics of Active Constrained Layer Damping

Abstract: Theoretical and experimental performance characteristics of the new class of actively controlled constrained layer damping (ACLD) are presented. The ACLD consists of a viscoelastic damping layer sandwiched between two layers of piezoelectric sensor and actuator. The composite ACLD when bonded to a vibrating structure acts as a “smart” treatment whose shear deformation can be controlled and tuned to the structural response in order to enhance the energy dissipation mechanism and improve the vibration damping characteristics. Particular emphasis is placed on studying the performance of ACLD treatments that are provided with sensing layers of different spatial distributions. The effect of the modal weighting characteristics of these sensing layers on the broad band attenuation of the vibration of beams fully treated with the ACLD is presented theoretically and experimentally. The effect of varying the gains of a proportional and derivative controller and the operating temperature on the ACLD performance is determined for uniform and linearly varying sensors. Comparisons with the performance of conventional passive constrained layer damping are presented also. The results obtained emphasize the importance of modally shaping the sensor and demonstrate the excellent capabilities of the ACLD.