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900 - A vibration isolation structure with the idea of phononic crystals
Wen J., Wang G., Yu D., Zhao H., Liu Y.
Abstract
The propagation of elastic wave in periodic composite called phononic crystals (PCs) has received a great deal of attention. Particular interests are focused on the existence of the so-called phononic band gaps (PBG) in which elastic waves are all forbidden. The study on PBG materials and structures is driven partly by potential applications such as elastic filters, vibrationless environments for high-precision systems.,etc. Only a few works about the applications of PCs has been published, but none of them has direct application in vibration isolation or attenuation. In this paper, we present a structure with the idea of PCs that can be used to isolate vibrations. Above all, a periodic binary straight beam with different cross sections is constructed. The band structures of flexural waves in the beam of infinite period are calculated with the plane-wave expansion (PWE) method. The vibration attenuation of a finite sample of the structure is calculated with the finite element method (FEM) and validated with a vibration experiment. Second, a vibration isolation structure is designed by using the feature of flexural wave band gaps of beam with periodic structure. Aluminum and Lucite bars with different rectangular cross sections are jointed together and arrayed alternatively in a framework of six layers. Each side of the layers in square shape consists of two symmetrically connected periods of the periodic straight beam. Four Aluminum blocks located at the four apexes (or at the mid of four sides) of each layer act as shoring connecting the layers one by one. The vibration attenuation is calculated with the finite element method (FEM), and an attenuation of about 20dB in the frequency range of the band gaps is found. Finally, the vibration attenuation of this structure is validated by a vibration experiment.
Citation
Wen J.; Wang G.; Yu D.; Zhao H.; Liu Y.: A vibration isolation structure with the idea of phononic crystals, 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