Topic
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.
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TL;DR: Investigation of active, constrained layer damping (ACLD) of smart, functionally graded (FG) plates revealed that the active patches of ACLD treatment significantly improve the damping characteristics of the FG plates over the passive damping.
Abstract: This paper deals with the investigation of active, constrained layer damping (ACLD) of smart, functionally graded (FG) plates. The constraining layer of the ACLD treatment is considered to be made of a piezoelectric, fiber-reinforced composite (PFRC) material with enhanced effective piezoelectric coefficient that quantifies the in-plane actuating force due to the electric field applied across the thickness of the layer. The Young's modulus and the mass density of the FG plates are assumed to vary exponentially along the thickness of the plate, and the Poisson's ratio is assumed to be constant over the domain of the plate. A finite-element model has been developed to model the open-loop and closed-loop dynamics of the FG plates integrated with two patches of ACLD treatment. The frequency response of the plates revealed that the active patches of ACLD treatment significantly improve the damping characteristics of the FG plates over the passive damping. Emphasis has been placed on investigating the effect of variation of piezoelectric fiber angle in the constraining layer of the ACLD treatment on the attenuating capability of the patches. The analysis also revealed that the activated patches of the ACLD treatment are more effective in controlling the vibrations of FG plates when the patches are attached to the surface of the FG plates with minimum stiffness than when they are attached to the surface of the same with maximum stiffness
21 citations
TL;DR: In this paper, a constrained-layer damping sandwich plate is considered, of which the apparent dynamic stiffness as function of frequency is determined using noncontact excitation and noncontact measurements.
21 citations
TL;DR: In this paper, a new 1-3 viscoelastic composite material (VECM) layer is designed in order to achieve improved passive damping characteristics of the unconstrained (UCLD)/constrained) layer damping treatment of structural vibration.
Abstract: A new 1-3 viscoelastic composite material (VECM) layer is designed in order to achieve improved passive damping characteristics of the unconstrained (UCLD)/constrained (PCLD) layer damping treatment of structural vibration. The present 1-3 VECM layer is used instead of traditional monolithic viscoelastic material (VEM) layer within the UCLD/PCLD treatment. The corresponding change in damping is studied through the static as well as dynamic finite element (FE) analyses of a substrate beam integrated with the UCLD/PCLD treatment. The static analysis reveals augmentations of damping in the use of 1-3 VECM layer. The dynamic analysis quantifies improvement in the passive unconstrained/constrained layer damping through the present design.
21 citations
TL;DR: In this article, a genetic algorithm is used to investigate the relationship of the viscoelastic layer thickness, the constraining layer thickness and the number of cuts initiated in the passive constrained layer damping (PCLD) treatment as they all relate to optimum damping of beams.
Abstract: The optimization of geometry and material properties of Passive Constrained Layer Damping (PCLD) treatments has been the subject of many research efforts in recent years. In this study, a genetic algorithm is used to investigate the relationship of the viscoelastic layer thickness, the constraining layer thickness, and the number of cuts initiated in the PCLD treatment as they all relate to optimum damping of beams. Genetic algorithms mimic the biological evolution process where potential solutions compete for survival based on their relative fitness. As a measure of the fitness of the PCLD treatment, a finite element model is used to compute the loss factor for the first mode of vibration with the capability of segmenting the treatment. It is found that, while the loss factor increases asymptotically with the increase in the viscoelastic layer thickness, an optimum constraining layer thickness for each viscoelastic layer thickness exists. The number of cuts in the segmented treatment tends to decrease wi...
21 citations
TL;DR: In this paper, the authors demonstrate the effect of active constrained layer segmentation on the enhancement of low frequency vibrations damping in flexible beams and compare the performance of segmented and unsegmented treatments, as well as active and passive treatments.
Abstract: The objective of this research is to demonstrate the effect of Active Constrained Layer segmentation on the enhancement of low frequency vibrations damping in flexible beams. The Active Constrained Layer Damping treatment, under consideration, consists of a viscoelastic layer sandwiched between two piezoelectric layers. The shear deformation of the viscoelastic layer causes loss of energy and thus the damping of vibration.This paper focuses on the effects of constraining layer segmentation. Experimental results obtained for slender beams partially treated with segmented and unsegmented Active Constrained Layer Damping treatments are presented. Tested specimens have low natural frequencies typical. e.g., for long span floors, moment frames, or flexible robotic manipulator arms. The performance of segmented and unsegmented treatments, as well as active and passive treatments are compared. The presented results demonstrate that significant improvement in Active Constrained Layer Damping treatment performance...
20 citations