橋梁動態載重識別之直接正規化法;Dynamic Loadings Identification of Bridge by the Direct Regularization Method

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Title:	橋梁動態載重識別之直接正規化法;Dynamic Loadings Identification of Bridge by the Direct Regularization Method
Authors:	陳士文;Chen,Shih-Wen
Contributors:	土木工程學系
Keywords:	L曲線法;Tikhonov正規化;動態程序化;動態載重識別系統;狀態空間系統;dynamic programming;L-curve;least square method;Tikhonov regularization;weight-in-motion
Date:	2013-05-23
Issue Date:	2013-06-19 15:19:26 (UTC+8)
Publisher:	國立中央大學
Abstract:	傳統上獲取卡車總重與各軸軸重的方法是將車輛停置於地磅站測重，此方法費時且占地，故關於測量車輛載重衍生出許多動態載重識別法（Weight-In-Motion）的研究，其中有一部份是著重於橋樑與車輛間互制行為的載重識別研究，稱作為橋梁動態載重識別（Bridge Weight-In-Motion），特色是由橋梁的力學反應來反算出通過車輛的總重與軸重，而本文的研究引用到工程學反算理論，研究目的是以橋梁的應變來反算出移動荷載，其中橋梁結構是用有限元素法來模擬分析，分階段從單純的二維梁元素模型，到三維梁以及版元素模擬；反算理論則是將傳統的結構動力方程式求解，藉由引入應用數學中動態程序化(Dynamic Programming)討論的近似解數列誤差量觀念、線性離散時間系統(Linear Discrete-Time System)裡面的狀態空間系統(State-Space System)和線性代數求解近似值用到的其中一種直接正規化法，如Tikhonov正規化，以建立出完整的橋梁動態載重識別法來反算識別出梁上移動載重。　　另外本論文除了利用數值模擬分析來觀察整個動態載重識別法可行性外，也實際進行實驗室單跨簡支梁的實驗分析案例，由分析結果探討加入許多不可抗拒之外在影響因素後，移動軸重識別結果精確度的變化，以下會概略介紹本文的研究主軸。In structural dynamics the forward problem is concerned with estimating theresponse of the structure with respect to time to a known forcing function. The inverseproblem is concerned with estimating the forcing functions that cause the system to bestmatch the known or measured response. The procedure utilised to solve this type ofinverse problem is known as the method of general inverse theory and uses three areas ofmathematics. These are least squares minimisation with regularisation such as Tikhonovregularisation, dynamic programming which provides an efficient solution to the leastsquares problem and finally the L-curve method to calculate the optimal regularisationparameter.In the numerical simulation, the inverse system is already useful to identify thepassing loads clearly on the simulate beam model. The system uses the strain reactions ofeach girder to calculate and monitor the bridge safety and maintenance. With this system,we’ll have a clear and accurate data about all the passing trucks’ loading.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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