電子元件在電路裝載模組下之震動與減震分析

本論文以建構數值模型的方法，探討電容器結構在承受衝擊時的動態反應，文中所用測試規範是依據MIL-STD-883F Method 2002.4 Mechanical Shock中所定義的半弦波訊號(1500G，500μsec)，經由數值分析軟體LS-DYNA分析電容器的衝擊動態反應與減震對策。模擬前先以方型鋁條進行模態測試實驗，驗證軟體ANSYS/Mechanical分析的準確性；經計算後顯示提高電容器的剛度可提高抗震性，但要注意是否引發共振。接著模擬衝擊產生器的真實衝擊實驗，發現模擬時承受最大應力處恰為實驗後回收實品的破壞位置。經分析電子元件受衝擊的摹擬結果得知，欲提高電子元件在電路裝載模組的抗震性，有兩個設計方向，第一是提高電子元件結構剛性，第二為設計減震結構，保護電路。綜合模擬結果，不同材料參數與承受震波方向會對結構的抗震性產生不同的影響，故進行減震設計前，應先分析所受主要衝擊方向，再尋找適當的材料，而設計時亦不應只提高物體剛性，應依據倍頻定律(Octave rule)，避免各元件在傳遞能量時，引發電子元件的共振模態。綜觀言之，減震設計除要減低待測元件的震動能量外，元件的頻率響應也需列入考量範圍。

關鍵字

LS-DYNA ；減震設計；震動分析

並列摘要

This thesis develops the numerical model to probe the dynamic response of a capacitor subjected to a shock wave which is based on the Military Standards. Finite element method (LS-DYNA) is utilized to analyze the dynamic behavior and vibrational control of the electronic components. The accuracy of simulation is verified by the experiments of modal testing of an aluminum bar and the impact of a shock generator. From the results of simulations, the vibrational resistance of the capacitor follows the increases of the rigidity of the structure. Avoiding the resonant frequency of the system is a significant concept of the design of vibrational control. The simulation results show that there are two ways to reduce shock energy: one way is to increase the rigidity of the system, and the other way is to design the shock protection structure. Different material properties and directions of shock waves result in various vibrational different resistances of the structure. Resonant frequency of the electronic component may be induced by the transmission of the energy.

並列關鍵字

LS-DYNA ； design of vibrational control ； analysis of vibration

參考文獻

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[3]S. Goyal, J. M. Papadopoulos, and P. A. Sullivan, “Shock Protection of Portable Electronic Products: Shock Response Spectrum, Damage Boundary Approach, and Beyond”, Shock and Vibration, Vol. 4, No. 3, pp. 169-191, 1997.

[5]S. Goyal, J. M. Papadopoulos, and P. A. Sullivan, “ The Dynamics of Clattering II：Global Results and Shock Protection”, Journal of Dynamic Systems, Measurement, and Control, Vol. 120, pp. 83-93, 1998b.

[6]李肇豪，電子裝置衝擊反應：以積分型逐步積分法及有限元素商業軟體為工具，國立臺灣大學土木工程學研究所碩士論文，2001。

[7]Z. Y. Zhu, and H. P. Lee, and B. T. Cheok, “Finite Element Analysis of Mechanical Shock Responses of RF Connectors”, Journal of Electronic Packaging, Vol. 125, pp. 144-152, 2003.

國際替代計量

電子元件在電路裝載模組下之震動與減震分析

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