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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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Journal ArticleDOI
TL;DR: In this paper, the optimal damping set could be found in a structure, in its fundamental vibration mode, such that the maximum modal loss factor of the system is achieved two different plate structures will be considered and the damping patches will be optimally located on them.

33 citations

ReportDOI
01 Jul 1980
TL;DR: In this article, a tutorial work in which the mechanisms by which large shear strain may be induced in a damping layer are explored is presented, and the parameters of the system which determine the effectiveness of constrained layer treatments are identified from analyses of several geometric configurations.
Abstract: : A tutorial work in which the mechanisms by which large shear strain may be induced in a damping layer are explored The parameters of the system which determine the effectiveness of constrained layer treatments are identified from analyses of several geometric configurations Advances of the past two decades in the design and analysis of damping layers as a means of controlling the amplitude of resonant vibrations are reviewed

33 citations

Journal ArticleDOI
TL;DR: In this paper, a patch placement process is developed which allows damping treatment to move on the structure and to distort its shape so as to improve the damping characteristics of the design.
Abstract: The QUAD4 element found in ASTROS is modified to include piezoelectric layers and a viscoelastic layer. These features are developed and combined to allow for active damping using piezoelectrics, passive damping using constrained layer damping (CLD) and hybrid damping in the form of active constrained layer damping (ACLD). These features are implemented in the QUAD4 element as additional layers in the composite layup definition. The development of these features are presented and the integrity of the implementation is validated by comparing with results found in the literature. A patch placement process is developed which allows the damping treatment to move on the structure and to distort its shape so as to improve the damping characteristics of the design. The structure and damping treatment are simultaneously designed for minimum weight with constraints on the frequency and damping ratio. Both beam and plate structures are used to illustrate this concept. A proportional-derivative controller is used for the active control of the beam and the linear quadratic regulator (LQR) is used to design the active controller for the plates.

32 citations

Journal ArticleDOI
TL;DR: In this article, damping augmentation in rotating composite beams via passive constrained layer damping (PCLD) has been evaluated in a vacuum chamber at rotational speeds ranging from 0 to 900 RPM.
Abstract: The first objective of this paper is to evaluate the performance of damping identification algorithms. The second objective is to determine the feasibility of damping augmentation in rotating composite beams via passive constrained layer damping (PCLD). Damping identification schemes were applied to four rectangular cross-section laminated composite beams with cocured integral damping layers over the span of the beam. The cocured beam consisted of a twenty-ply balanced and symmetric cross-ply Gr/Ep composite host structure, a top and bottom damping layer of viscoelastic material (VEM), and a 2-ply Gr/Ep constraining layer sandwiching the viscoelastic material to the host structure. Four VEM thicknesses were considered: 0, 5, 10, and 15 mils. The cantilevered beams were tested at rotational speeds ranging from 0 to 900 RPM in a vacuum chamber. Excitation in bending was provided using piezo actuators, and the bending response was measured using full strain gauge bridges. Transient data were analysed using logarithmic decrement, a Hilbert transform technique, and an FFT- based moving block analysis. When compared to the beam with no VEM, a 19.2% volume fraction (15 mil layer) of viscoelastic in the beam produced a 400% increase in damping ratio in the non-rotating case, while at 900 RPM, the damping ratio increased only 360%. Overall structural damping was reduced as a function of RPM, due to centrifugal stiffening.

32 citations

Journal ArticleDOI
TL;DR: In this paper, sound radiation from a panel into an enclosure is attenuated using active constrained layer damping (ACLD) that is controlled by an adaptive least mean square (LMS) algorithm.
Abstract: Sound radiation from a panel into an enclosure is attenuated using active constrained layer damping (ACLD) that is controlled by an adaptive least mean square (LMS) algorithm. Five of the enclosure walls are rigid and the other wall, which is flexible, is made of a 0.4064 mm thick aluminum plate. The plate is partially treated with ACLD, which consists of a visco-elastic sheet sandwiched between two piezo-electric films. One of the piezo-films is bonded to the surface of the plate and used directly to control the plate vibration whereas the second piezo-film is utilized to control the shear deformation of the visco-elastic layer to enhance its energy dissipation characteristics. In this manner, the sound radiation can be controlled by active and/or passive control strategies with each operating separately, when the first film is activated, or in unison when the second film is energized in response to the sound pressure inside the enclosure. Comparisons are made between the effectiveness of the two control strategies in attenuating the sound radiation into the enclosure. The results indicate that combining active and passive controls, as in the case of the ACLD treatment, is more effective in controlling the sound radiation. Moreover, such a control strategy is found to require lower control inputs than when the active and passive control actions are used separately.

32 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202227
202123
202020
201927
201826