複合材料板的振動及聲射分析

Abstract

複合材料板之振動及聲射分析 研究生:卓永剛 指導教授:金大仁 博士 國立交通大學機械工程研究所 中文摘要 本文目的在討論複材積層板之振動特性以及發展利用有限單元分析軟體ANSYS所得到之振幅、相位角與聲壓方程式結合來繪聲壓曲線的方法，並討論在不同的邊界條件、激振器位置下聲壓曲線的變化，並找出聲壓曲線突然下降之原因。 在理論部分，本篇論文使用有限單元分析軟體ANSYS建立複材板進行模態分析與簡諧激振響應分析，將簡諧激振響應分析所得到之振幅、相位角與正確的聲壓方程式結合，完成繪聲壓曲線的方法，與實驗得到的聲壓曲線作比較，確定用ANSYS繪製聲壓曲線的正確性與可行性。並使用ANSYS 作簡諧激振響應分析所得到之振幅、相位角、振形結合自然頻率的模態與振形來解釋聲壓曲線產生谷(Valley)之原因。分析在不同的邊界條件、激振位置對聲壓曲線的影響，並由激振位置及振動模態之間的關係研究使聲壓曲線保持平坦的方法。 在實驗部份，量測在不同的邊界條件、激振器位置所得聲壓曲線與理論作比較，並解釋兩者間具有差異之原因。以幫助我們了解複材板之振動形行為。

Vibration and Sound Radiation of Laminated Composite Plates Student : Yong-Gang Jhuo Advisor : Dr. Tai-Yan Kam Institute of Mechanical Engineering National Chiao Tung University ABSTRACT In this thesis,vibration characteristics of laminated composite plates are studied and the amplitude and phase angle obtained from the finite element software ANSYS together with sound pressure equation are used to construct sound pressure response curves. Sound pressure responses with different boundary conditions and different locations of exciter are also studied and the reason why sound pressure response curves fluctuate drastically is analyzed. In the theoretical study, the modal analysis and the harmonic analysis of laminated plates are achieved using the finite element software ANSYS.The amplitude and phase angle obtained from the harmonic analysis together with sound pressure equation are used to plot sound pressure response curves and then the results are compared with the experimental results to make sure the present method is correct.Studying the relations among the amplitudes,phase angles and mode shapes obtained from the harmonic analysis and modal analysis ,one can explain why sound pressure curve has valley. In the experimental study, sound pressure responses of the plates with different boundary conditions and different locations of exciter are generated and used to verify the theoretical results.We have found ways to improve the smoothness of the sound pressure response curves using the relationship between locations of exciter and modal response.