本文主要討論蘭姆波在含有週期結構之薄板中傳遞的行為，設計兩種不同的週期結構，對其進行有限元素模擬，觀察週期結構的波傳特性並進行參數研究，最後透過實驗量測進行比較與驗證。

數值模擬部分，首先觀察無結構均質薄板之波傳特性，並藉由不同傳遞模態的位移場特徵對模態進行分類，將頻帶結構中不屬於蘭姆波的色散曲線移除，以降低分析頻帶結構的難度。接著分別討論在薄板中週期排列圓洞以及圓柱體的結構，同樣將頻帶結構做模態篩選與分類後再行觀察，可以發現部分頻段沒有蘭姆波之色散曲線存在，即屬於蘭姆波之能隙，透過全波模擬打入特定模態的蘭姆波並計算穿透率可以驗證頻帶結構觀察到的能隙現象。最後分別對兩種週期結構進行幾何參數分析，觀察不同形成機制之能隙對幾何參數變化上的差異。

實驗量測部分，本研究使用PVDF線聚焦壓電換能器量測系統進行量測，利用頻域量測法分析量測數據後可得到結構的頻帶結構峰值圖，圖中峰值連線即為傳遞波之色散曲線，對不同尺寸之圓洞與圓柱型試片進行量測，並將量測結果與數值模擬結果進行比對，以相互確認模擬與實驗結果之可信度。綜合模擬與實驗，本研究整合出一套聲子晶體平板的分析流程，有利於聲子晶體平板元件的設計。

In this study, we discuss the behaviors of Lamb wave propagating on the plate with periodic structures, which are so-called phononic crystal plates. Two kinds of phononic crystal structures are considered, which are named “hole-type” and “pillar-type”, respectively. We employ finite element method to investigate the special wave propagating phenomena of the structure, such as band gaps and changes of wave velocity, then we utilize the experimental method, which is based on a PVDF line-focus transducer, to investigate the samples with these periodic structures, and compare the experimental results with numerical results.

In the part of numerical simulation, we calculate the band structures of the plates with two kinds of phononic crystals, the band structures show the absence of specific Lamb wave modes dispersion curves in some frequency ranges, namely the band gaps of Lamb wave, and the mechanisms that lead to band gaps are discussed. We also do the geometric parameter analysis to further investigate the reaction of different band gaps and dispersion curves to the geometric parameters.

In the part of experimental measurement, we use the experiment system with PVDF line-focus transducer to measure the samples that contain phononic crystal structures. The decrease of wave velocity and band gaps can be found in measurement results, which are consistent with simulation results. Based on this research, we can bulid a complete process of the analysis of phononic crystal plates.

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