CAE技術在樑與板結構產品的動態特性分析與應用

本論文之主要目的是運用CAE技術探討樑與板結構產品的動態特性，對於外型近似樑與板結構之產品進行振動模態實驗分析，並且探討所模擬的樑與板結構邊界的正確性，此外以輸入各種外力訊號而固定雷射位移計的方式對樑與板結構產品進行振動模態實驗，由實驗獲得一組結構頻率響應函數與相對應的關聯性函數，再經由有限元素數值分析法得到結構的模態參數。有限元素數值分析法是以ANSYS軟體對樑與板結構產品進行結構動力學分析。實驗則利用頻譜儀器及其振動量測軟體量取激振器實際在樑與板結構上激振所產生的振動信號，再利用ME’scopeVES軟體作模態分析，分析出前六個模態及其對應頻率以瞭解其相關振動的現象，並與ANSYS所求得的資料比較。根據以上研究步驟與方法，將可以獲得各種樑與板結構產品的頻率響應函數、關聯性函數及模態參數，加以設計振動控制方法可使得各種樑與板結構產品的工作頻率範圍落在相關零件產品的共振頻率之外，避免樑與板結構產品產生過大振幅，甚至超過容許應力或應變範圍而導致破壞現象的發生。結果顯示理論分析、數值分析與實驗量測所得的結果驗證相當吻合，包括頻率響應函數、自然頻率、模態阻尼與振型，證明所模擬架構之樑與板結構產品實驗模型的正確性。此一樑與板結構產品模型可以作為振動量測與實驗模態分析教具，亦可更進一步從事樑結構與板結構產品的振動分析與控制的應用研究。

關鍵字

模態分析；頻率響應函數；自然頻率；數值分析；模態參數

並列摘要

The main objective of this paper is using CAE techniques to find the dynamic properties for beam and plate structure products. We use the beam and plate structure products in market to perform the experimental modal analysis ( EMA ) and verify the accuracy of the boundary conditions of the beam and plate structure products. The modal testing of the beam and plate structure products is performed by giving an external force signal which produced from function maker to shaker and fixing the optoelectronic displacement measurement system. A series of frequency response functions (FRFs) is obtained as well as the corresponding coherence functions. By the finite element numerical analysis, the structural modal parameters can be determined. The goal of using FEA is to carry on vibration analysis to the beam and plate structure products by ANSYS. Using the frequency spectrum instrument software and hardware to obtain the measured data and perform the structural dynamic analysis on the beam and plate structure products. Simultaneously, one can use the ME’scopeVES software to perform modal analysis. The first six modal shapes and frequencies can be analyzed by CAE experiment tools. One can compare the ANSYS numerical data with the experiment data to understand the phenomenon of related products. Emplying the above CAE hardware/software tools and the appropriate method, one will be able to acquire the FRF, modal parameters and correlation functions of various beam and plate structure products. One can also design the vibration control method in order to avoid the working frequency scope of various beam and plate structure products fallen inside the resonance frequency scope of the related products. It won’t produce large amplitude and exceed the allowable stress and strain limit of the beam and plate structure products to avoid the failure phenomenon on the products. Results show that the experimental and theoretical results, including FRFs, natural frequencies, modal damping and mode shape, agree well. The constructed beam structure and plate structure products is validated and can be used as the demonstration tools of vibration measurement and EMA as well as for the further study of the structural vibration control.