| Author: | Xia, Jiajun |
| Title: | A new type of sonic black hole device for sound absorption |
| Degree: | M.Sc. |
| Year: | 2022 |
| Subject: | Absorption of sound Metamaterials Noise control Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | vii, 74 pages : color illustrations |
| Language: | English |
| Abstract: | Noise control has always been a serious concern in many fields, such as automotive and aviation industries. Existing noise control approaches, like using mufflers or traditional sound absorption materials, are not efficient for low frequency noise control. Despite the great efforts made by many researchers, the problem has still not been solved. The recent emergence of acoustic metamaterials shows new possibilities for potentially solving this problem. More specifically, a so-called acoustic black hole (ABH) structure has been proposed for sound and vibration control due to its appealing features in achieving effective energy trapping and dissipation. So far, the research on ABH mainly concentrates on flexural wave manipulation in structures like beams or plates. However, its exploration for sound reduction and control, referred to as sonic black hole (SBH), is quite limited. In this dissertation, we investigated a SBH structure lined with micro-perforated panels (MPPs) inside. The main target is that this new perforation-modulated SBH can maximize the SBH effects and achieve low frequency and broadband sound absorption. Meanwhile, it can be put into practical use with a simpler internal configuration. The study will emphasis on exploring the physical phenomenon behind SBH as well as evaluating its sound absorption performance from both theoretical and experimental perspective. More specifically, transfer matrix method (TMM) is adopted here to build the theoretical model to analyze the parametric influence on SBH effects. Finite element simulation (FEM) is then carried out to calculate the sound absorption coefficient with experimental validation following behind. Meanwhile, experiment results also reveal the existence of the slow-wave effect. The proposed perforation-modulated SBH shows great potential to deliver good sound absorption performance. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 6881.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 4.39 MB | Adobe PDF | View/Open |
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