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Abstracts & Full Papers
615 - Influence of damping treatment on sound radiation
Feng L.
Abstract
Damping treatment is a common way in industry to reduce the vibration of a structure and also to reduce the sound radiated from that. Previous theoretical analyses and practical investigations have shown that damping treatment is a good way to reduce structural vibration, while not that efficient when the radiated sound is concerned, since the radiation efficiency of the structure might be increase greatly. This problem is further investigated in this paper, for a steel panel and for panels used in railway cars. Results show that when a constrained layer damping treatment is applied and when mechanical excitation is used; the averaged vibration velocity level of the panel is reduced of about 10 dB, while the radiated sound power is reduced of about only 1 dB. The reason for that is investigated. It is noticed that the near-field radiation around the excitation point has a big contribution for the sound radiated, which is more important for a damped structure than for a structure with little damping. Besides that, the radiation efficiency of the panel is also increased because of the increased stiffness. This agrees with the theoretical prediction. Physics behind the phenomenon is discussed. Alternative methods for damping treatment, which can ideally reduce both vibration and sound radiation, have also been investigated and tested.
Citation
Feng L.: Influence of damping treatment on sound radiation, CD-ROM Proceedings of the Thirtheenth International Congress on Sound and Vibration (ICSV13), July 2-6, 2006, Vienna, Austria, Eds.: Eberhardsteiner, J.; Mang, H.A.; Waubke, H., Publisher: Vienna University of Technology, Austria, ISBN: 3-9501554-5-7