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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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01 Mar 1974
TL;DR: In this paper, the effect of constrained layer damping treatments on cabin noise levels in an HH-53C helicopter was evaluated for various flight conditions, including hover, forward flight and banked.
Abstract: : The report describes some of the results of an investigation to evaluate the effect of constrained layer damping treatments on cabin noise levels in an HH-53C helicopter. Vibration and noise levels were measured for various flight conditions, including hover, forward flight and banked, and in each case it was observed that the damping treatment reduced vibration and noise levels in certain frequency bands within which natural modes of vibration were strongly excited. Ground vibration tests under artificial excitation and laboratory vibration tests on simpler but related structures were also conducted to further understand the phenomena involved and to develop appropriate damping treatments for broad temperature range noise control applications.

2 citations

Journal ArticleDOI
TL;DR: In this paper, a curved aluminium plate with an ACLD treatment formed by mounting a large piezoceramic patch with Araldite 2027 was examined by ultrasonic Lamb waves generated by the patch.
Abstract: This work was conducted as part of the European Union project ARTIMA and it investigates the potential for a dual use active constrained layer damping treatment for both vibration control and structural health monitoring. It examines a curved aluminium plate with an ACLD treatment formed by mounting a large piezoceramic patch with Araldite 2027. The plate was investigated by ultrasonic Lamb waves generated by the patch, and several smaller piezoceramic transducers were used as sensors. Damage was simulated by adding incrementally increasing saw cuts to the plate, and the technique of outlier analysis was used to classify when this damage had occurred.

2 citations

Proceedings ArticleDOI
07 Apr 2008
TL;DR: Nayeh et al. as mentioned in this paper used the modal curve fitting method and the power input method to estimate the damping loss of honeycomb sandwich plates with different particle damping treatments.
Abstract: Damping loss factors of honeycomb sandwich plates with different par ticle damping treatments are estimated both experimentally and analytically. Particle dampers are made by filling different glass microbubbles into honeycomb cells. Damping is experimentally estimated using two methods: the modal curve -fitting method and t he power input method. Both damping estimation methods yield consistent loss factor estimations. Then peak damping performances are analytically explained by fluid resonances in a cavity. The relationship between the peak damping values is explained by int ernal friction among particles. The internal friction of different particles is evaluated by angle of repose test and flowability test. Applicability of this fluid model of particles is discussed. This technique shows the potential for designing high level particle damping in distinct frequency bands, which is of interest for aircraft interior noise suppression. I. Introduction ARTICLE damping is a passive vibration reduction technique enabled by the use of an enclosure filled with particles made of a varie ty of materials. The energy loss is basically due to the friction and impact between the particles. Unlike other commonly used passive damping approaches (e.g., constrained layer damping and tuned mass absorber), particle damping can be used over a broad r ange of temperature and frequencies due to its intrinsic characteristics. However, the mechanism of particle damping is still not fully understood. It is already found to be closely related to many factors, including particle size, particle density, partic le shape, particle surface friction, vibrational direction, packing ratio, vibration amplitude, etc. Witt and Kinra 1 considered single and multiple layers of smooth, steel spheres in rectangular enclosures. The measured time -history of the velocity decay at the tip of the steel beam (where the damper was attached) was used to compute the change in kinetic energy per cycle (called the “specific damping capacity”) at 20 Hz. They noted that the specific damping capacity generally increased with particle size, and changed significantly with the clearance between the particles and the enclosure. Nayfeh, Verdirame and Varanasi 2

2 citations

Journal ArticleDOI
TL;DR: In this paper, the free vibration and damping characteristics of rotating shaft with passive constrained layer damping (CLD) are studied, where a composite beam theory taking into account transverse shear deformation is employed to model the composite shaft and constraining layer.
Abstract: The free vibration and damping characteristics of rotating shaft with passive constrained layer damping (CLD) are studied. The shaft is made of fiber reinforced composite materials. A composite beam theory taking into account transverse shear deformation is employed to model the composite shaft and constraining layer. The equations of motion of composite rotating shaft with CLD are derived by using Hamilton’s principle. The general Galerkin method is applied to obtain the approximate solution of the rotating CLD composite shaft. Numerical results for the rotating CLD composite shaft with simply supported boundary condition are presented; the effects of thickness of constraining layer and viscoelastic damping layers, lamination angle, and rotating speed on the natural frequencies and modal dampings are discussed.

2 citations

Journal ArticleDOI
TL;DR: In this article, a hybrid passive damping system consisting of a constrained layer damping and a resonant shunt circuit is presented for suppressing the multiple vibration modes of beams in a wide frequency band.
Abstract: The modeling of a hybrid passive damping system is presented for suppressing the multiple vibration modes of beams in this paper. This hybrid passive damping system consists of a constrained layer damping and a resonant shunt circuit. In a passive mechanical constrained layer damping, a viscoelastic layer, which is sandwiched between a host structure and a cover layer, is used to suppress vibration amplitudes in the high frequency range. A passive electrical damping is designed for targeting the vibration amplitude in the low frequency range. The governing equations of motion of the hybrid passive damping system are derived through the Hamilton's principle. The obtained mathematical model is validated experimentally. The theoretical and experimental techniques presented provide an invaluable tool in controlling the multiple vibration modes across a wide frequency band.

2 citations


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