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基于小波变换原理,采用Mexican hat小波对结构由于刚度降低引起的损伤进行损伤诊断。以损伤结构应变模态的奇异信号作为检测指标进行小波变换,通过小波系数模极大值确定损伤时间,讨论Lips-chitz指数与损伤程度的关系。以一个RC剪力墙刚度损伤检测为例,建立试验室模型进行试验。试验结果表明,该方法能够准确检测损伤时间,同时讨论了影响Lipschitz指数大小的因素和基于不同小波函数的选取对检测结果的影响,经过比较发现针对应变模态的奇异信号应用Mexican hat小波分析效果最好。
Based on the principle of wavelet transform, the Mexican hat wavelet is used to diagnose the damage of the structure due to the decrease of the stiffness. The singular signal of structural damage modal damage was used as the detection index to carry out wavelet transform. The damage time was determined by the modulus maxima of wavelet coefficients. The relationship between the Lipschitz index and the degree of damage was discussed. Taking a RC shear wall stiffness damage detection as an example, a laboratory model is established for testing. The experimental results show that this method can accurately detect the damage time, discusses the factors that affect the size of Lipschitz index and the influence of the selection based on different wavelet functions on the detection results. By comparison, Mexican hat wavelet analysis is applied to singular signals with strain modes the best.