| Author: | Zhou, Tong |
| Title: | Vibration control utilizing 'acoustic black hole' effect |
| Advisors: | Cheng, Li (ME) |
| Degree: | M.Sc. |
| Year: | 2017 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Vibration -- Control Structural dynamics |
| Department: | Faculty of Engineering |
| Pages: | 75 pages : color illustrations |
| Language: | English |
| Abstract: | The ‘Acoustic Black Hole’ (ABH) effect can be exploited for flexural vibration suppressions in thin-walled structures. Conventional ABH structures, however, are tied with the inherent structural weakness due the low local stiffness required and possibly high stress concentration caused by the small residual thickness of the ABH taper, thus limiting their practical applications. In this thesis, the dynamic and static properties of an embedded double-layered compound ABH beam are investigated through numerical simulations. It is shown that, whilst ensuring effective ABH effect, the compound ABH structure allows a significant improvement in the static properties of the structure. For the former, the compound design is shown to outperform its counterpart in the conventional ABH configuration in terms of damping enhancement and vibration suppression. For the latter, the compound ABH structure is also shown to provide much better static properties in terms of structural stiffness and strength. Furthermore, the structural damping can be further improved by using an extended platform at the tip of power-law profile, which meanwhile improves the structural strength but reduces the structural stiffness. Therefore, when choosing the platform length, a balance needs to be struck among the desired ABH effect and the mechanical properties of the structure. Experimental measurement was also conducted to confirm the validity of the FEM analyses as well as the superior ABH effect of the compound ABH beams. To further improve the static and dynamic properties, compound ABH beams with an enlarged width are also investigated by numerical simulations. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991021962224303411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.78 MB | Adobe PDF | View/Open |
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