以移動荷載診斷橋樑結構強度之研究

Diagnosing Structural Stiffness of Bridges by a Moving Load

黃瑞昇(JuiSheng Huang)

指導教授 ： 黎文龍

國立臺北科技大學/機電學院/機電整合研究所/碩士(2013年)

摘要

本研究主要利用能量損耗的觀念，進行橋樑結構強度的診斷。利用新近發展的結構耗能鑑別方法，以激振力當作輸入訊號施加於橋樑結構系統，再量測該系統之輸出訊號的穩態響應，將輸入訊號與輸出訊號做乘積調變，經快速傅立葉轉換可得到頻率響應圖，並觀察傅立葉係數直流位準與二倍頻位準以計算出系統能量損耗且比對橋樑結構損壞前後耗能差異，並且將耗能差異以百分比表示之。
在動態模擬中，觀察橋樑結構體在不同損壞程度下的結構特性。由結果顯示，結構體的能量損耗隨著不同的損壞程度有明顯的變化，隨著損壞程度越高其結構損壞前後之能量損耗差異有上升的趨勢。且透過單位向量之概念延伸出單位能量損耗，藉此可一次性檢測出橋樑結構損壞位置，改善了原本要比對損壞前後差異之二次性及多次性檢測，並提以移動荷載之方法作為激振力以實行於實際橋樑。
在實驗驗證方面，本研究製作近似橋樑之結構模型，分別在不同的損壞情況下量測結構動態特性，並且對橋樑結構體進行鑑別以及驗證一次性檢測。

關鍵字

橋樑結構 ； 結構能量損耗 ； 結構診斷 ； 移動荷載

並列摘要

In this study, the use of dissipative energy for diagnosing structural stiffness of the bridges. Use new identification method to calculate dissipative energy for bridges, the method is accomplished by processing the response signal with respect to that of input.
In other word, one is measure the steady state response signal of the system, which is excited by an input sinusoidal signal. Once the response signal is obtained. It can be modulated by two different reference signals. The required dissipative energy can be thus extracted from the modulated by the given equation through its Fourier coefficient. And observe the Fourier coefficient to calculate dissipative energy. And the dissipative energy will be the damage objective.
In dynamic simulation to observe the structural characteristics of the bridges in the different degree of damage. The results showed that the structure of dissipative energy with the obvious changes in the different degree of damage. And find method of one-time detection of damage location of bridges. And provide method of moving loads as the exciting force to large bridges.

並列關鍵字

Bridges ； Structural Dissipative Energy ； Structural Diagnosis ； Moving Loads

參考文獻

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