壓電平板的振動及聲傳分析

Abstract

本文主要研究壓電材料與附著板黏合的結構在壓電受到電壓驅動時所產生的振動現象及聲壓的表現。 結構方向，主體均將壓電材料與銅板黏合，再以彈性懸邊固定。針對不同結構進行振動實驗及聲壓值量測。 理論部份則利用有限元素軟體建構壓電平板之分析模型，進行自然振動頻率、自然振動模態及簡諧響應分析，並將每個節點之位移及相角代入聲壓程式中計算得到每個頻率下之聲壓值，並繪製聲壓曲線圖。 比較實驗與摸擬之聲壓曲線，討論各種參數對聲壓曲線之影響，藉以了解壓電平板之激振機制及影響聲壓曲線各種因素。並加以改善，本文針對不同材料參數、邊界條件及改變幾何形狀所產生之聲壓曲線做分析，依據分析結果做結構設計，以期改善壓電致動平板只適合用於高頻處的缺點。

The purpose of the study is to investigate the vibration characteristics and the performance of sound pressure level (SPL) of piezo-electrically excited radiating plates. For the experimental design, the piezoelectric plates was bonded with the copper plate, and the structure was supported by elastic suspensions around the surrounding of the copper plate. Three different structures of the radiating plates were analyzed. The natural frequency and the sound pressure were measured from the experiments. In comparison with the FEM software-ANSYS, the results of the experiments were used to study the effects of different designs of the radiating of the radiating panels on the SPL curve and verify the suitability of the models in predicting sound radiation. The influences of the parameters, such as the material constants, boundary conditions and the shape of the structures, on the SPL were explored in this thesis. According to the results of the analyses, it is possible that a proper design of the structure of a radiating panel can improve the narrow application of traditional piezo-electrically excited plates which can only find applications in high frequency range.