地震作用下结构时变物理参数识别
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摘要
利用小波分析函数多尺度逼近方法,将剪切型结构在地震作用下时变的阻尼和刚度用尺度函数的线性组合表示,将时变参数的辨识问题转化为由已知的正交尺度函数和系统的输入输出来估计线性组合中的时不变系数问题,用最小二乘法对剪切型框架结构在地震作用下时变的刚度和阻尼进行了有效的辨识。此方法无需事先假定系统参数的时变规律,在有噪声情况下可以用Tikhonov正则化方法减小识别方程的不适定性对识别结果的影响。数值算例表明了该方法的有效性。
This paper presents a wavelet method for the parametric identification of nonlinear system.By expanding the time-varying stiffness and damping into linear combination of a series scaling functions, the time-varying parameters identification problem is turned to the problem of identifying invariant coefficients,which can be identified by least-square method when the input and output of the structure and the scaling function are known.By this method,the nonlinear shear type structure under earthquake loadings can be better identified and the nonlinear characteristics of the system are not need to be known before identifying.The Tikhonov regularization method reduces the influence of ill condition and obtains the fairly good identification results when measurement noise is existing.Simulations are presented to prove the effectiveness of this method.
This paper presents a wavelet method for the parametric identification of nonlinear system.By expanding the time-varying stiffness and damping into linear combination of a series scaling functions, the time-varying parameters identification problem is turned to the problem of identifying invariant coefficients,which can be identified by least-square method when the input and output of the structure and the scaling function are known.By this method,the nonlinear shear type structure under earthquake loadings can be better identified and the nonlinear characteristics of the system are not need to be known before identifying.The Tikhonov regularization method reduces the influence of ill condition and obtains the fairly good identification results when measurement noise is existing.Simulations are presented to prove the effectiveness of this method.
引文
[1]Pavlenko O V,Loh C H.Nonlinear system identification of reinforced concrete steel structure:using pseudodynamic testing data[J].Journal ofEngineering Mechanics,2004,130(7):836-847.
[2]Loh C H,Lin C Y,Huang C C.Time domain identification of frames under earthquake loadings[J].Journal of Engineering Mechanics,2000,126(4):693-703.
[3]Yang J N,Lin S.Identification of parametric variations of structures based on least squares estimation and adaptive tracking technique[J].Jour-nal of Engineering Mechanics,1999,125(2):290-298.
[4]Lin J W,Betti R.On-line identification and damage detection in non-linear structural systems using a variable forgetting factor approach[J].Earthquake Engineering and Structural Dynamics,2004,33:419-444.
[5]尚久铨.建筑物模态参数时变特性基于强震记录的识别[J].地震工程与工程振动,1991,13(4):22-31.
[6]许强,黄润秋.地震作用下结构非线性响应的突变分析[J].岩土工程学报,1997,19(4):25-29.
[7]张广莹,邓正隆.小波分析在系统辨识中的应用[J].电机与控制学报,2002,16(1):64-67.
[8]罗晓,陈耀,孙优贤.基于小波包分解的非线性时变系统辩识[J].高校应用数学学报A辑,2004,19(1):51-56.
[9]徐长发,李国宽.实用小波方法[M].武汉:华中科技大学出版社,2004.
[10]陈逢时.子波变换理论及其在信号处理中的应用[M].北京:国防工业出版社,1998.
[2]Loh C H,Lin C Y,Huang C C.Time domain identification of frames under earthquake loadings[J].Journal of Engineering Mechanics,2000,126(4):693-703.
[3]Yang J N,Lin S.Identification of parametric variations of structures based on least squares estimation and adaptive tracking technique[J].Jour-nal of Engineering Mechanics,1999,125(2):290-298.
[4]Lin J W,Betti R.On-line identification and damage detection in non-linear structural systems using a variable forgetting factor approach[J].Earthquake Engineering and Structural Dynamics,2004,33:419-444.
[5]尚久铨.建筑物模态参数时变特性基于强震记录的识别[J].地震工程与工程振动,1991,13(4):22-31.
[6]许强,黄润秋.地震作用下结构非线性响应的突变分析[J].岩土工程学报,1997,19(4):25-29.
[7]张广莹,邓正隆.小波分析在系统辨识中的应用[J].电机与控制学报,2002,16(1):64-67.
[8]罗晓,陈耀,孙优贤.基于小波包分解的非线性时变系统辩识[J].高校应用数学学报A辑,2004,19(1):51-56.
[9]徐长发,李国宽.实用小波方法[M].武汉:华中科技大学出版社,2004.
[10]陈逢时.子波变换理论及其在信号处理中的应用[M].北京:国防工业出版社,1998.
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