Download or read book Predicting the Effect of Viscoelastic Constrained layer Damping Treatment on the Vibroacoustic Response of a Structure written by Blair Joy Cohen and published by . This book was released on 1989 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Viscoelastic Constrained Layer Damping for Structural Application written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 34 (thesis year 1989) a total of 13,377 theses titles from 26 Canadian and 184 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 34 reports theses submitted in 1989, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Download or read book Vibro acoustic Studies on Damped Panels Using Finite and Boundary Element Methods written by Jimit Shah and published by . This book was released on 2002 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibration Damping written by Ahid D. Nashif and published by John Wiley & Sons. This book was released on 1991-01-16 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical approach to the application of viscoelastic damping materials to control vibration and noise problems in industrial structures, machinery, computer machinery, and vehicles. Assuming a basic understanding of mechanical engineering, the text covers implementation of theory, including material properties, dynamic structural response, design procedures and practical applications. Based on an understanding of both the properties of materials and the vibrational response of structures. Considers individual structures and the damping materials properties simultaneously. Includes extensive collection of data sheets for a large number of useful damping materials.

Download or read book Research and Development Needs in Finite Element Analysis of Viscoelasticity Damped Structures written by David Kienholz and published by . This book was released on 1980 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibration control in structures by means of viscoelastic damping material has gained wide acceptance, particularly in the aerospace industry. Significant weight, cost, performance, and reliability payoffs are possible in situations where resonant vibration cannot be avoided. Numerous examples of damping by constrained or unconstrained layers of viscoelastic material have appeared in the literature. However, the analysis of general structures to predict the damping due to an integral or add-on layered treatment or lumped viscoelastic elements is by no means a routine activity. The key to effective use of the well-developed technology of damping materials-will be a parallel improvement in analytical capability. It will be necessary to make reliable and timely predictions of the system damping which can be expected when a given viscoelastic material is incorporated into a given structural configuration. It must also be possible for working engineers to produce these answers in a project environment using widely available analysis tools such as computer codes. It is natural to look to finite element methods for damping predictions of general damped structures, just as they are used for routine calculation of the dynamic properties of undamped systems. Considerable work has already been done in this area, primarily aimed at prediction of damped response of simple structural elements such as sandwich beams, plates, etc. As participants in this work, it has been the authors' experience that current finite element tools show-much promise for analysis of structures which include viscoelastic damping material. However as with any emerging technology, there are specific questions, both theoretical and practical, which must be investigated and resolved in order to produce a reliable and useful design tool. The purpose of this paper is to describe the problem areas which, in the authors' view, must be addressed in the near term.

Download or read book Constrained Viscoelastic Layer Damping of Thick Aluminum Plates written by Michael John Bateman and published by . This book was released on 1990 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern naval warfare has been increasingly dependent upon the acoustic silencing of the participants. Constrained viscoelastic layer damping of vibrating elements is one method which can be used to meet acoustic silencing goals. This paper considers constrained viscoelastic layer damping treatments applied to a thick aluminum plate, including single layer, double layer, a milled pocket plate, and a milled 'floating element' configuration. High modal damping values were obtained for each damping configuration. The Modal Strain Energy method, using finite element analysis to estimate modal loss factors, was investigated for use as a tool in constrained viscoelastic layer damping design. A comparison of experimentally measured frequency response and modal loss factors with those predicted by the modal stain energy method is presented to confirm the possible use of the modal strain energy method as a design tool. Keywords: Vibration, Damping, Viscoelastic material, Constrained layer damping. (JS).

Download or read book Analytical and Experimental Investigation of Constrained Viscoelastic Layer Damping for a Plate and Shell Model written by James Robert Nault and published by . This book was released on 1988 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).

Download or read book Active and Passive Vibration Damping written by Amr M. Baz and published by John Wiley & Sons. This book was released on 2019-04-08 with total page 751 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Integrated System Damping and Isolation of a Three Dimensional Structure written by James A. Speer and published by . This book was released on 1996-03-01 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlling the vibratory response of a mechanical system is of key importance in most modern engineering designs. Constrained viscoelastic layered damping of vibrating elements is one method that can be used for vibration reduction. This thesis deals with an integrated system damping and excitation source isolation scheme of a three dimensional structure. Use of a validated finite element model of the system to predict system dynamic behavior proved to be an effective method in the design of the constrained viscoelastic layered damping treatment. Direct frequency response analysis was performed on the structure with the damping treatment applied and excitation source isolated. Experiments were also performed on the structure without the damping treatment tp provide reference data for comparison purposes.

Download or read book Vibration Damping of Structural Elements written by Chin-Teh Sun and published by Prentice Hall. This book was released on 1995 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibration and vibration control of structures play a vital research role in mechanical, aerospace, and civil engineering, as well as many industrial and defense-related applications. This volume presents state-of-the-art technology in the area of vibration damping of discrete and continuous structural systems.

Download or read book Vibro acoustic Analysis of a Thin Cyclindrical Shell with Minimal Passive Damping Patches written by Ron Taulbee and published by . This book was released on 2013 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: An experiment is designed to measure the vibro-acoustic effects of minimal constrained layer damping patches applied to a thin cylindrical shell. A patch placement procedure developed for rectangular plates is adapted for the cylindrical shell application. The procedure proposes placing damping patches on the structural anti-nodes of the vibrating structure for significant noise and vibration reduction. First, impact testing is performed to determine the first 11 non-zero natural frequencies and mode shapes of the shell. Next, vibration and acoustic responses are measured under harmonic excitation of the shell using an electrodynamic shaker. These responses are measured for the untreated shell as well as multiple damping patch treatment configurations. The results verify the ability to treat certain modes as specified by the adapted procedure. Over the frequency range from 200 to 1500 Hz, reductions in vibration response of 2-8 dB and in radiated noise of 3-11 dB are measured with patches covering only two percent of the shell surface area. Finite element and boundary element models are developed to computationally predict changes in radiation efficiency. System damping measured from vibration testing is applied to the computational model to simulate the effects on radiated noise due to the additional damping introduced by the patches. The integrated structural-acoustic computational model shows a trend of radiated noise reduction as system damping increases; however, the predicted radiated noise reduction exhibits a large spread and does not seem to follow a one-to-one correlation with the reduction in damping. These results suggest additional complexities in the modal radiation efficiencies and assumed damping values are present, which should be addressed in future studies.

Download or read book Nonlinear Vibration Analysis and Optimal Damping Design of Sandwich Cylindrical Shells with Viscoelastic and ER fluid Treatments written by Farough Mohammadi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aerospace Structures Technology Damping Design Guide Volume 2 Design Guide written by and published by . This book was released on 1985 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume represents the basic design guide for the application of viscoelastic damping to primarily aerospace structures. Simplified design equations for the vibration response of structures and for the free layer, constrained layer and tuned damper damping applications are presented. These equations are to be used with the damping material data in Volume III to develop the required design. For more complex structures, the above analysis should be supplemented by finite element analysis also discussed in this volume. The other topics included in this volume are the factors contributing to vibration problems in aerospace type structures including a summary of the vibration environments; a discussion of the design approach including when each of the three damping treatments should be used; examples on the use of the design equations, design examples and case histories of successful applications viscoelastic damping, and a discussion of other practical design considerations; a summary of the damping in aerospace materials and structures; and finally, a summary of material properties for typical aerospace metals and composite materials. Keywords: structural vibration response equations, viscoelastic damping design approach, viscoelastic damping design equations, example problems, viscoelastic damping design applications, case histories, other design considerations, damping in composites, damping in metals, damping in aerospace structures, metal material properties, conversion tables.

Download or read book Vibration Response of Constrained Viscoelastically Damped Plates written by Gerald J. Maurer and published by . This book was released on 1987 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The frequency response analysis of several constrained viscoelastically damped plates were performed with modifications to account for the frequency dependent properties of viscoelastic materials (loss factors and shear modulus) using MSC/NASTRAN. A modal strain energy approximation method was also applied to each plate. Comparisons of the frequency response analysis to the modal strain energy method were made for each plate structure. The experiments were performed on the plates to establish the base line data for the comparisons. The modal strain energy method frequency response plots showed good agreement with the frequency response analysis method plots for all plate structures analyzed. Plate structures with fewer natural frequencies in the frequency range investigated showed better agreement between the two prediction methods than the structures with more natural frequencies. Keywords: Viscoelastic material; Modal strain energy method; composite frequency response curves, Theses.

Download or read book A Study of Constrained Layer Viscoelastic Damping Treatments and Their Application to Flexible Mechanisms written by Carl L. Sisemore and published by . This book was released on 2001 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active and Passive Vibration Damping written by Amr Mahmoud Sabry Baz and published by . This book was released on 2019 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.