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Structure damage identification under ambient excitation based on dynamic entropy mutative-scale symbolic time series analysis

DOI：

 作者 单位 E-mail 李庆洲 大连理工大学 917249270@qq.com 李东升 大连理工大学土木工程学院 dsli@dlut.edu.cn

摘 要： 针对环境激励下结构损伤识别困难的问题，提出了一种基于动态熵的变尺度符号化方法，结合虚拟脉冲响应函数，利用变尺度符号化形成的编码序列内蕴结构整体频率变化的丰富信息这一原理对结构进行损伤识别。该方法首先计算环境激励下结构的虚拟脉冲响应函数，然后利用所提出的基于动态熵的变尺度符号化方法计算各子序列的频数，以此作为概率特征向量计算损伤指标判断结构损伤与否及其损伤程度。在MATLAB中数值模拟了一个3自由度链式结构的算例，最后将该方法应用于美国洛斯阿拉莫斯国家实验室（LANL）的一个4自由度板柱结构进行不同程度的损伤识别。试验结果表明：环境激励下基于动态熵的变尺度符号化结构损伤识别方法能够有效地判定结构初期损伤的发生，并且可以准确比较结构损伤的不同程度。

Abstract: To solve the difficult problem of structural damage identification under ambient excitation, a new method based on dynamic entropy mutative-scale symbolic time series analysis is proposed. Combined with the virtual impulse response function, this method applies the principle that coding sequence contains the rich information of the overall structure frequency changes to conduct structural damage identification. This method firstly calculates the virtual impulse response function of the structure under ambient excitation, and then works out the frequency of each sub-sequence based on the dynamic entropy mutative-scale symbolic time series analysis as the probability feature vector that will be used to calculate the damage index to determine the damage and characterize the damage degree of the structure. To evaluate the effectiveness and reliability the proposed method is applied to a MATLAB numerical model and a test-bed structure tested at Los Alamos National Laboratory (LANL). It is shown that the proposed method works well in identifying the occurrence of the initial structural damage under ambient excitation, and can accurately determine the damage severity.
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