【作者】 相敏； 施袁锋； 熊峰；

【Author】 Min Xiang;Yuanfeng Shi;Feng Xiong;Department of Civil Engineering,College of Architecture and Environment,Sichuan University;

【机构】 四川大学建筑与环境学院土木工程系；

【摘要】 在强激励作用下或服役过程中结构性能退化的影响下,工程结构通常表现出非线性和时变特征,且结构参数的这种变化是影响结构性能的重要指标。因此,对工程结构时变性能的合理描述和及时追踪,有助于结构的安全性评估和全寿命管理。小波多尺度近似凭借其高效的局部时频近似功能,在参数识别领域得到了广泛的应用。本文基于小波多尺度近似理论,研究框架结构在强震作用下的结构杆件刚度和阻尼出现时间变化特性时的结构时变参数估计问题。考虑到框架梁和柱的时变损伤程度通常是不同的,本文通过建立同时包含平动和转角自由度的时变动力模型,来分别估计梁和柱的时变刚度。因此,本文提出的方法可应用于识别梁或柱子的时变损伤情况。通过数值模拟,考虑结构参数渐变和突变的不同情况以及不同测量噪音程度影响下,来验证所提出的框架结构时变参数识别方法的有效性。更多还原

【Abstract】 Engineering structures usually exhibit nonlinear and time-varying behavior when subjected to strong excitation or due to material deterioration under operation. This behavior is one of the key properties affecting the structural performance. Hence, reasonable description and timely tracking of the time-varying properties of engineering structures are necessary for the safety assessment and life-cycle management of structures. Due to its powerful ability of approximating functions or signals in the time-frequency domain, wavelet multi-resolution analysis has been widely applied in the field of parameter estimation. In this paper, identification of the time-varying structural parameters including both the damping and stiffness coefficients of frame structure under strong earthquake excitation is studied using the wavelet multi-resolution approximation. Considering that the damage levels of beam elements and column elements are usually different, a time-varying dynamical model including both the translational and rotational degrees of freedom is established in order to estimate the stiffness coefficients of both beams and columns. Numerical examples are given to demonstrate the performance of the proposed approach. Both gradual and abrupt changes of beams and columns under various levels of measurement noise are studied and discussed.更多还原