| Author: | Li, Jieming |
| Title: | Wave propagation and coupling characteristics in nonlinear elastic metamaterials |
| Advisors: | Cheng, Li (ME) |
| Degree: | M.Sc. |
| Year: | 2022 |
| Subject: | Metamaterials Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | x, 91 pages : color illustrations |
| Language: | English |
| Abstract: | In recent years, the research on acoustic metamaterials has become a hot topic, especially on linear elastic metamaterials. This dissertation will focus on the analyses of the nonlinear elastic metamaterials. In order to analyze and understand the wave propagation and coupling characteristics in nonlinear systems, two typical fundamental nonlinear periodic structures, namely a nonlinear periodic monoatomic chain and a granular crystal chain, are investigated. Analytical modelling and numerical simulations are applied to study these structures. Two common methods, the perturbation method and the harmonic balanced method, are used for theoretical calculation of the nonlinear monoatomic chain to solve the corresponding equation of motion and nonlinear dispersion relation. Corresponding numerical models are established through Simulink and Matlab, followed with the analyses and comparisons between analytical and numerical results. The amplitude-dependent curves, frequency response curves and the transmission curves are exploited to observe the phenomena of wave propagation and coupling. Meanwhile, an experimental model of the granular crystal chain is set up with tests conducted for comparisons and verification of typical physical phenomena revealed by numerical analyses. In particular, the generation and the variation of amplitude of the low-frequency coupled waves, through wave mixing arising from the nonlinearity in the system, are studied. Analyses offer useful guidance for the generation of low frequency and high energy coupled waves. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 6877.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 4.56 MB | Adobe PDF | View/Open |
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