2019-08-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/661651摘要：近年來，物聯網的發展提升了無線感測之需求，也帶動了振動能量採集的發展。本計畫提出引入磁力之U型能量採集器，利用磁力的非線性提升採集器在基底激振的採集頻寬及功率；此外，也將安裝一個圓柱體於U型採集器上，使其可產生渦流誘發振動，並探討U型採集器在風能採集下的動態響應。本研究將分為三階段進行，第一階段將分析U型採集器在加入磁力後，其所帶來的非線性因素對採集效能的影響。也將從位能的觀點，探討在雙方向採集下，單穩態及雙穩態下對採集頻寬的影響。理論模型將利用拉格朗日方程式進行推導，並與實驗結果進行驗證；第二階段探討U型採集器之多模態對於渦流誘發式風能採集所帶來之效益。由於渦流誘發式風能採集僅在特定風速範圍內有高能量輸出，而此特定風速與結構之共振頻率相關，因此本研究預期能藉由U型結構的多模態特性拓展採集器適用的風速範圍，也將針對圓柱體及結構的參數進行最佳化，以提升採集器之性能。在理論模型上，將利用尾流振蕩子模型作為流體模型之基礎，配合U型結構之方程式及壓電項推導出系統之動態方程式。我們也將建立風洞、進行實驗，並與理論模型交互驗證；第三階段探則進一步探討引入磁力非線性之U型採集器在風能採集之成效，分析磁力非線性及其所帶來的單穩態及雙穩態特性對於渦流誘發式能量採集所能帶來的效益。在理論模型部份，考量U型採集器在二維空間中的運動，將利用力分解模型為流體模型之基礎建立其系統方程式，並與風洞實驗之結果驗證。<br> Abstract: Recently, the development of Internet of Things has aroused the demand for wireless sensors and stimulated the growth of vibration energy harvesting. In the project, a magnet-induced U-shaped piezoelectric energy harvester is proposed. It is expected to improve the harvesting bandwidth and power by utilizing the nonlinearity from magnetic force. Besides, the U-shaped harvester will be attached with a cylinder for vortex-induced wind energy harvesting. The dynamics of the U-shaped harvester will be investigated and modeled. This project is conducted in three phases. In the first phase, the magnet-induced U-shaped energy harvester will be analyzed. The benefit of the nonlinearity brought by the magnetic force on the performance of the harvester will be investigated. The analysis will also be conducted from the point of view of potential energy. The impact of mono-stable and bi-stable states on the harvesting bandwidth in the two orthogonal directions of vibration will be analyzed and discussed. The theoretical model will be derived based on Lagrange’s equation and validated with the experimental results. In the second phase, we will investigate the benefit of the multimodality of the U-shaped structure on vortex-induced vibration energy harvesting. For vortex-induced vibration energy harvesting, the harvester can only produce high power output within a specific range of the wind speed, which is correlated to the natural frequencies of the structure of the harvester. Therefore, it is expected that the range of the wind speed with high power output will be expanded by adopting the multimodality of the U-shaped harvester. The parameters of the cylinder and the U-shaped structure will also be optimized to improve the performance of the harvester. The theoretical model will be derived based on the wake oscillator model, the dynamics equations of U-shaped structure, and the piezoelectric term. A wind tunnel will be built for the experiment and the results will be compared with the theoretical model. In the final phase, we will further discuss the influence of magnetic nonlinearity of the U-shaped harvester on wind energy harvesting. The impact of mono-stability and bi-stability brought by the magnets on vortex-induced vibration energy harvesting will be investigated. Two-dimensional motions of the U-shaped harvester will be considered in the theoretical model. The force decomposition model will be adopted to derive the system equations and validated with the experimental results.壓電振動能量採集磁力非線性渦流Piezoelectricvibration energyenergy harvestingmagnetic forcenonlinearvortex