Acoustic Radiation Damping of Vibrating Structures

1963 ◽  
Vol 35 (3) ◽  
pp. 369-377 ◽  
Author(s):  
R. A. Mangiarotty
Keyword(s):  
Acoustic Radiation ◽  
Radiation Damping ◽  
Vibrating Structures

Acoustic Radiation Damping

1985 ◽  
Vol 107 (4) ◽  
pp. 357-360 ◽  
Author(s):  
B. L. Clarkson ◽  
K. T. Brown
Keyword(s):  
Acoustic Radiation ◽  
Radiation Damping

Computation of acoustic radiation from vibrating structures in motion

2008 ◽  
Vol 69 (12) ◽  
pp. 1154-1160
Author(s):  
Yong-Bin Zhang ◽  
Chuan-Xing Bi ◽  
Xin-Zhao Chen ◽  
Jian Chen
Keyword(s):  
Acoustic Radiation ◽  
Vibrating Structures

On the Applications of the Boundary-Element Method to Acoustical Field Studies of Vibrating Structures

1986 ◽  
Vol 108 (4) ◽  
pp. 454-461 ◽  
Author(s):  
J. K. Jiang ◽  
M. G. Prasad
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Sections ◽  
Acoustic Radiation ◽  
Field Studies ◽  
Boundary Integral ◽  
Method Of Images ◽  
Element Size ◽  
Vibrating Structures ◽  
Element Method

This paper describes the applications of the Boundary-Element Method (BEM) for studies on acoustical field of various vibrating structures. The studies emphasize the numerical aspects of the BEM. Both acoustical near and far fields of the vibrating structures are investigated in this work. The vibrating structures considered in this application studies are a circular piston in an infinite, rigid baffle and cantilever-type beams. In the case of piston in an infinite baffle, instead of using the method of images, the free-space Green’s function is used to evaluate boundary integral equation by including both piston and baffle surfaces. The influence of the stationary baffle in the case of piston is further investigated. The beams considered are of both rectangular and circular cross sections. The results obtained by BEM have compared well with the available results from classical methods. The studies indicate that in the application of BEM in such problems both the element size and the number of elements including stationary surface have significant effect on the results obtained. The studies have yielded that very good results are obtained when the largest dimension of an element is equal to 0.2 times the acoustic wavelength (in air) of the frequency of acoustic radiation.

Radiation Efficiency of Convected Fluid Loaded Plates

1999 ◽  
Author(s):  
Kenneth D. Frampton
Keyword(s):  
Elastic Plate ◽  
Acoustic Radiation ◽  
Sound Radiation ◽  
Coupled Model ◽  
Plate Motion ◽  
Fluid Loading ◽  
Fluid Medium ◽  
Fluid Field ◽  
Vibrating Structures ◽  
Model Approach

Abstract The radiation of sound from geometrically simple vibrating structures into stationary fluids is well understood. However, to date, very few investigations have considered the effects that a convected fluid has on structural acoustic radiation. The purpose of this investigation is to quantify the effects of changes in flow velocity on the sound radiated from a vibrating elastic plate into a convected fluid medium. The discussion will include a description of modeling an elastic plate imbedded in an infinite baffle and radiating into a semi-infinite convected fluid field. Furthermore, the importance of a coupled model approach (where the fluid pressures generated by the plate motion in turn force the plate response) will be discussed. It will be demonstrated that the effects of convected fluid loading on sound radiation can be very significant.

Rationale Abklärung von Lebererkrankungen

2017 ◽  
Vol 74 (3) ◽  
pp. 79-86
Author(s):  
Leona von Köckritz ◽  
Andrea De Gottardi
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Alkalische Phosphatase ◽  
Gamma Glutamyltransferase ◽  
Alpha 1 Antitrypsin

Zusammenfassung. Im klinischen Alltag werden häufig erhöhte Leberwerte beobachtet. In der Regel erfordern sie weitere Abklärungen bezüglich der möglichen Ätiologie und des Schweregrad einer akuten oder chronischen Lebererkrankung. Die Abklärung sollte dabei neben einer gezielten Anamnese und sorgfältigen klinischen Untersuchung, auch die Bestimmung von laborchemischen Markern für Cholestase und Leberfunktionsstörungen (wie Alkalische Phosphatase, gamma-Glutamyltransferase, Bilirubin, Albumin und Gerinnungsfaktoren) umfassen. Die Bestimmung weiterer Parameter wie Ferritin und Transferrinsättigung, Autoimmunantikörper, Virusserologien, alpha-1 Antitrypsin und Coerulolasmin können weitere Hinweise für die kausalen Zusammenhänge der Leberfunktionsstörung liefern. Bei Patienten mit Lebererkrankungen ist eine sonografische Beurteilung der Leber obligat. Ergänzend zur Sonografie werden heute weitere nicht-invasive Methoden wie Fibroscan, Acoustic Radiation Force Impulse Elastometrie und Magnet-Resonanz-Elastografie zur Beurteilung der Leberfibrose eingesetzt. In ausgewählten Fällen ist eine Leberbiopsie notwendig, um den Grad der Fibrose und die Ätiologie der Lebererkrankung zu eruieren. Mithilfe eines Fallbeispiels, diskutieren die Autoren im Folgenden die rationale Anwendung diagnostischer Tests und deren korrekte Interpretation und schlagen eine Orientierungshilfe zur rationalen Abklärung von Patienten mit Lebererkrankungen vor.

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