Theoretical Simulation of Damping Effect Base on Experimental Measurement

基於實驗模態量測對阻尼比效應之模擬

王栢村(Bor-Tsun Wang) ； 李建興(Jane-Xing Li) ； 許家振(Jia-Jen Shiu)

《中華民國振動與噪音工程學會論文集》 2007 (2007/06) Pp. 35-40

https://doi.org/10.30028/CSSVANNUAL.200706.0035

摘要

阻尼效應一般而言無法由理論分析求得，而經由實驗模態測試可獲得模態阻尼比。本文介紹兩種由實驗量測所得阻尼比套入理論分析模型之模擬方法。第一種方法係假設結構為比例黏滯阻尼模型，可基於實驗模態分析所量得之阻尼比對質量與勁度矩陣相關之兩常數進行最佳化分析，可由所得最佳常數值進一步求得比例黏滯阻尼系統之黏滯阻尼矩陣。第二種方法則將實驗模態分析所得之各模態阻尼比加以累加並平均，可假設阻尼比為常數且應用於理論模型分析。最後並以實際案例說明實務上如何於理論模型分析中模擬阻尼比效應，並與實驗模態分析所得之頻率響應函數結果相比較。未來可於任意結構之阻尼比效應模擬中，以此兩種方法，使阻尼比參數有一參考值作為輸入。

關鍵字

實驗模態測試 ； 黏滯阻尼模型 ； 最佳化分析 ； 累加平均阻尼比 ； 比例阻尼

並列摘要

In general, damping effect can not be theoretically determined. However, modal damping ratios can be obtained via experimental modal testing. This paper presents two methods to include damping effect into the theoretical model base on the experimentally determined damping data. First, the proportionally, viscously damped model is assumed. The optimization problem is formulated to determine two optimum constants related to mass and stiffness matrices with the known experimental modal damping ratios, and so forth the proportional, viscous damping matrix can be determined from these two constants. Second, the accumulated averaged damping ratio can be obtained from the experiments and adopted to define the constant modal damping ratio for the analytical model. Several case studies are presented to show the implement of damping effect in theoretical analysis such that the analytical model can be more practically simulated in accordance with the experimental test results. The developed methodology is easy to implement and applicable to finite element analysis for arbitrary structures.

並列關鍵字

experimental modal testing ； viscously damped model ； optimization problem ； accumulated averaged damping ratio ； proportional damping