A Study of Constrained Layer Viscoelastic Damping Treatments and Their Application to Flexible Mechanisms PDF Download

Author: Carl L. Sisemore
Publisher:
ISBN:
Category : Damping (Mechanics)
Languages : en
Pages : 450

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Author: Carl L. Sisemore
Publisher:
ISBN:
Category : Damping (Mechanics)
Languages : en
Pages : 312

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Author: James Robert Nault
Publisher:
ISBN:
Category :
Languages : en
Pages : 96

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The use of constrained viscoelastic layer damping treatments has recently been found to be effective in reducing unwanted resonant vibrations in structures. The proper design of such damping treatments has been difficult, however, since closed form equations to describe system behavior can only be used for simple beams and plates. In addition, finite element analysis has been difficult since the material properties of viscoelastic materials show a marked dependence on frequency and temperature, resulting in the need to run an excessive number of finite element analyses for each design a proper constrained viscoelastic layer damping treatment for a test structure consisting of two concentric cylinders connected by four vanes. Constrained Layer Damping, Plates, Shells finite elements modeling. (mjm).

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Category :
Languages : en
Pages :

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The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping. Ross, Kerwin and Unger (RKU) model for passive viscoelastic damping has been used to predict damping effects in constrained layer sandwich cantilever beam. This method of passive damping treatment is widely used for structural application in many industries like automobile, aerospace, etc. The RKU method has been applied to a cantilever beam because beam is a major part of a structure and this prediction may further leads to utilize for different kinds of structural application according to design requirements in many industries. In this method of damping a simple cantilever beam is treated by making sandwich structure to make the beam damp, and this is usually done by using viscoelastic material as a core to ensure the damping effect. Since few years in past viscoelastic materials has been significantly recognized as the best damping material for damping application which are usually polymers. Here some viscoelastic materials have been used as a core for sandwich beam to ensure damping effect. Due to inherent complex properties of viscoelastic materials, its modeling has been the matter of talk. So in this report modeling of viscoelastic materials has been shown and damping treatment has been carried out using RKU model. The experimental results have been shown how the amplitude decreases with time for damped system compared to undamped system and further its prediction has been extended to finite element analysis with various damping material to show comparison of harmonic responses between damped and undamped systems.

Author: Amr M. Baz
Publisher: John Wiley & Sons
ISBN: 1118481925
Category : Technology & Engineering
Languages : en
Pages : 751

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A guide to the application of viscoelastic damping materials to control vibration and noise of structures, machinery, and vehicles Active and Passive Vibration Damping is a practical guide to the application of passive as well as actively treated viscoelastic damping materials to control vibration and noise of structures, machinery and vehicles. The author — a noted expert on the topic — presents the basic principles and reviews the potential applications of passive and active vibration damping technologies. The text presents a combination of the associated physical fundamentals, governing theories and the optimal design strategies of various configurations of vibration damping treatments. The text presents the basics of various damping effective treatments such as constrained layers, shunted piezoelectric treatments, electromagnetic and shape memory fibers. Classical and new models are included as well as aspects of viscoelastic materials models that are analyzed from the experimental characterization of the material coefficients as well as their modeling. The use of smart materials to augment the vibration damping of passive treatments is pursued in depth throughout the book. This vital guide: Contains numerical examples that reinforce the understanding of the theories presented Offers an authoritative text from an internationally recognized authority and pioneer on the subject Presents, in one volume, comprehensive coverage of the topic that is not available elsewhere Presents a mix of the associated physical fundamentals, governing theories and optimal design strategies of various configurations of vibration damping treatments Written for researchers in vibration damping and research, engineers in structural dynamics and practicing engineers, Active and Passive Vibration Damping offers a hands-on resource for applying passive as well as actively treated viscoelastic damping materials to control vibration and noise of structures, machinery and vehicles.

Author: S. Jantawon
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: E. M Kerwin (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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Segmenting (periodic interruption) increases the effectiveness of a constrain-layer damping treatment for flexural waves at frequencies below the peak damping for the continuous system. The interruption of the constraining layer results in induced strains in the viscoelastic layer, giving higher dissipation than for the continuous system. There is an optimum segment length for a given treatment. Discusses the application of segmented constrained layers to the damping of extensional waves. There are significant parallels with the flexural wave case; the optimum segment length for a given damping treatment is essentially the same. As with flexural waves, the results apply below an upper frequency limit. Achievable loss factors for extensional waves are lower than for flexural waves for a given system cross section. Mechanical attachment of the constrained-layer damping treatment is sometimes required. Damping performance is compromised to the extent that the constraining layer lateral deflection is inhibited. Quantitative results on the effect of a point fastener are reported. Results are given for the treatment effective area lost due to a rigid fastener, and for a fastener of finite lateral stiffness. These results can guide the design of fasteners to minimize their effect on performance. (Author).

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ISBN:
Category :
Languages : en
Pages :

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This study investigates the optimal topology of a constrained layer damping treatment involving viscoelastic materials under a static load for different boundary conditions in order to maximize the damping loss factor for the first vibrating mode of the base structure. Different parameter studies are carried out for the two boundary conditions and conclusions are drawn based on the loss factor results and the novel topologies that emerge from these optimization results. The novel topologies are then used to interpret shapes that are more reasonable to manufacture. Tremendous improvement in the loss factor (up to 1250%) is obtained by topology optimization in many of the cases. Also this study develops fundamental understanding of the optimal topologies that are required to maximize the loss factor.

Author: Blair Joy Cohen
Publisher:
ISBN:
Category :
Languages : en
Pages : 218

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Author:
Publisher: Allied Publishers
ISBN: 9788170239581
Category :
Languages : en
Pages : 762

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