In situ determination of loss and coupling loss factors by the power injection method
TL;DR: In this article, inversion of the linear power balance equations is used to determine the plate loss factors and the coupling loss factors in situ, and good agreement is obtained between the predicted and measured coupling loss factor and between the in situ loss factor, for each plate separately also in steady state from power injection measurements.
About: This article is published in Journal of Sound and Vibration.The article was published on 1980-05-22. It has received 181 citations till now. The article focuses on the topics: Coupling loss & Loss factor.
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TL;DR: In this paper, the analysis of noise and vibration signals is presented. But the authors focus on a case study of pipe flow noise and vibrations and use it as a diagnostic tool.
Abstract: Preface Acknowledgements Introductory comments 1. Mechanical vibrations: a review of some fundamentals 2. Sound waves: a review of some fundamentals 3. Interactions between sound waves and solid structures 4. Noise and vibration measurement and control procedures 5. The analysis of noise and vibration signals 6. Statistical energy analysis of noise and vibration 7. Pipe flow noise and vibration: a case study 8. Noise and vibration as a diagnostic tool 9. Worked examples Appendices Problems Answers to problems Index.
648 citations
TL;DR: In this article, the authors investigate statistical energy analysis for analyzing the vibrational behavior of complex structures and apply it to sound and vibration transmission in the field of solid-state physics.
Abstract: Theories for analysing the vibrational behaviour of complex structures are examined, parallels being drawn with several other areas of physics in which problems of wave propagation in inhomogeneous media are studied. There are three main stages to the investigation. First, the response to random driving of a single, essentially homogeneous, system is examined. The second, and much more detailed, discussion concerns energy transport between discrete coupled subsystems. In particular, the authors investigate an approach to this problem which is known as statistical energy analysis. The third main topic is the phenomenon of Anderson localisation as it applies to certain problems of sound and vibration transmission-the phenomenon is much better known in the field of solid-state physics. Applications of it to vibration are of interest in themselves, and also shed light on the theoretical basis of statistical energy analysis, which is a diffusive transport theory.
129 citations
TL;DR: In this article, the authors present a theoretical approach to calculate SEA Coupling Loss Factor (CLF) for subsystems modelled with FEM, which takes into account complicated substructures that can be encountered in practical industrial application.
99 citations
TL;DR: In this paper, the authors used the finite element method (FEM) to calculate the vibrational energies of plates forming L and H-structures at discrete frequencies between 10 and 2000 Hz, where one plate is excited by a point force and the power is transmitted through the junction to the other plates.
70 citations
66 citations
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01 Jan 1973TL;DR: In this article, the authors consider bending waves, which are a special combination of compressional and shear waves, and for some special cases (quasi-) longitudinal waves and torsional waves also have to be considered.
Abstract: Although sound waves in structures cannot be heard directly, and only be felt at low frequencies, they play an important role in noise control, because many sound signals are generated or transmitted in structures before they are radiated into the surrounding medium. In several respects sound waves in structures and sound waves in gases or liquids are similar, there are, however, also fundamental differences, which are due to the fact that solids have a certain shear stiffness, wheras gases or liquids show practically none. As a consequence acoustic energy can be transported not only by the normal compressional waves but also by shear waves and many combinations of compressional (sometimes loosely called longitudinal) and shear waves . For noise control purposes bending waves (which are a special combination of compressional and shear waves) are of primary importance; for some special cases (quasi-) longitudinal waves and torsional waves also have to be considered.
1,085 citations
TL;DR: In this paper, the authors consider bending waves, which are a special combination of compressional and shear waves, and for some special cases (quasi-) longitudinal waves and torsional waves also have to be considered.
Abstract: Although sound waves in structures cannot be heard directly, and only be felt at low frequencies, they play an important role in noise control, because many sound signals are generated or transmitted in structures before they are radiated into the surrounding medium. In several respects sound waves in structures and sound waves in gases or liquids are similar, there are, however, also fundamental differences, which are due to the fact that solids have a certain shear stiffness, wheras gases or liquids show practically none. As a consequence acoustic energy can be transported not only by the normal compressional waves but also by shear waves and many combinations of compressional (sometimes loosely called longitudinal) and shear waves . For noise control purposes bending waves (which are a special combination of compressional and shear waves) are of primary importance; for some special cases (quasi-) longitudinal waves and torsional waves also have to be considered.
934 citations
Book•
15 Sep 1975
TL;DR: The statistical energy analysis (SEA) method as discussed by the authors is a general framework of methods rather than a particular technique for the analysis of mechanical vibrations. And it has been used extensively in the design of aircraft, spacecraft launch vehicles, ships, and similar structures.
Abstract: This is the first full exposition in print of a subject in whose development over the past fifteen years the author has been a prime participant. As an approach to the study of mechanical vibrations, statistical energy analysis (SEA) has found new applications and adherents with each passing year. The name SEA was coined to emphasize the essential feature of the approach: "Statistical" indicates that the dynamical systems under study are presumed to be drawn from statistical populations or ensembles in which the distribution of the parameters is known. "Energy" denotes the primary variable of interest. "Analysis" is used to underscore the fact that SEA is a general framework of methods rather than a particular technique.Vibration is a ubiquitous problem for mechanical engineers, especially those concerned with the design of aircraft, spacecraft launch vehicles, ships, and similar structures composed of such elements as plates and beams. SEA provides the designer with a method for estimating the response characteristics of such structures to vibratory excitations, from which he can predict the potential for structural fatigue, component failure, and human discomfort caused by noise or excessive vibration levels. SEA is particularly appropriate in applications involving relatively large and lightweight structures, such as those designed for aerospace use. These statistical models are also helpful to mechanical designers who are charged with making environmental and vibratory response estimates at a stage in a project whese structural detail is not yet known. Moreover, SEA provides an approach to a number of vibration problems that cannot, from a practical viewpoint, be solved by classical methods.
541 citations
129 citations
TL;DR: In this paper, the sharing of energy by connected, randomly vibrating structures can be estimated using a statistical approach using a modal energy as the primary variable; the structures are described statistically by their modal densities, masses and loss factors Average response levels are computed in addition, response variations are calculated to establish confidence coefficients for estimates related to these average levels.
Abstract: The sharing of energy by connected, randomly vibrating structures can be estimated, using a statistical approach Modal energy is taken as the primary variable; the structures are described statistically by their modal densities, masses, and loss factors Average response levels are computed In addition, response variations are calculated to establish confidence coefficients for estimates related to these average levels The method is applied to two cases: a single resonator attached to a plate and two plates attached together Experimental studies are reported that support the methods
87 citations