Observatorio de I+D+i UPM

Memorias de investigación
Research Publications in journals:
INDUCED DAMPING ON VIBRATING CIRCULAR PLATES SUBMERGED IN STILL FLUID
Year:2015
Research Areas
  • Aeroacustics and vibrations
Information
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. Keywords: Circular plate; fluid-structure; natural frequencies; fluid influence on damping
International
Si
JCR
Si
Title
INTERNATIONAL JOURNAL OF APPLIED MECHANICS
ISBN
1758-8251
Impact factor JCR
1,624
Impact info
Datos JCR del año 2014
Volume
7
10.1142/S1758825115500799
Journal number
6
From page
1
To page
18
Month
DICIEMBRE
Ranking
Participants
  • Autor: Manuel Gascon Perez (UPM)
  • Autor: Pablo Garcia-Fogeda Nuñez (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Desarrollo y Ensayos Aeroespaciales
  • Centro o Instituto I+D+i: Instituto Universitario de Microgravedad "Ignacio da Riva"
  • Departamento: Aeronaves y Vehículos Espaciales
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