Induced Damping on Vibrating Circular Plates Submerged in still Fluid

Gascón Pérez, Manuel and Garcia-Fogeda Nuñez, Pablo (2015). Induced Damping on Vibrating Circular Plates Submerged in still Fluid. "International Journal of Applied Mechanics", v. 7 (n. 6); pp. 1-18. ISSN 1758-8251. https://doi.org/10.1142/S1758825115500799.

Description

Title: Induced Damping on Vibrating Circular Plates Submerged in still Fluid
Author/s:
  • Gascón Pérez, Manuel
  • Garcia-Fogeda Nuñez, Pablo
Item Type: Article
Título de Revista/Publicación: International Journal of Applied Mechanics
Date: December 2015
ISSN: 1758-8251
Volume: 7
Subjects:
Freetext Keywords: circular plate; fluid-structure; natural frequencies; fluid influence on damping
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Aeronaves y Vehículos Espaciales
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

When a structure vibrates immersed in a fluid it is known that the dynamic properties of the system are modified. The surrounding fluid will, in general, contribute to the inertia, the rigidity and the damping coefficient of the coupled fluid-structure system. For light structures, like spacecraft antennas, even when the fluid is air the contribution to the dynamic properties can be important. For not so light structures the ratio of the equivalent fluid/structure mass and rigidity can be very small and the fluid contribution could be neglected. For the ratio of equivalent fluid/structure damping both terms are of the same order and therefore the fluid contribution must be studied. The working life of the spacecraft structure would be on space and so without any surrounding fluid. The response of a spacecraft structure on its operational life would be attenuated by the structural damping alone but when the structure is dynamically tested on the earth the dynamic modal test is performed with the fluid surrounding it. The results thus are contaminated by the effects of the fluid. If the damping added by the fluid is of the same order as the structural damping the response of the structure in space can be quite different to the response predicted on earth. It is therefore desirable to have a method able to determine the amount of damping induced by the fluid and that should be subtracted of the total damping measured on the modal vibration test. In this work, a method for the determination of the effect of the surrounding fluid on the dynamic characteristics of a circular plate has been developed. The plate is assumed to vibrate harmonically with the vacuum modes and the generalized forces matrix due to the fluid is thus computed. For a compressible fluid this matrix is formed by complex numbers including terms of inertia, rigidity and damping. The matrix due to the fluid loading is determined by a boundary element method (BEM). The BEM used is of circular rings on the plate surface so the number of elements to obtain an accurate result is very low. The natural frequencies of the system are computed by an iteration procedure one by one and also the damping fluid contribution. Comparisons of the present method with various experimental data and other theories show the efficiency and accuracy of the method for any support condition of the plate.

More information

Item ID: 40413
DC Identifier: http://oa.upm.es/40413/
OAI Identifier: oai:oa.upm.es:40413
DOI: 10.1142/S1758825115500799
Official URL: https://www.worldscientific.com/doi/abs/10.1142/S1758825115500799
Deposited by: Memoria Investigacion
Deposited on: 12 Jul 2016 11:23
Last Modified: 04 Jun 2019 17:41
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