离散空间小波分析的环境荷载下桥梁的损伤识别

Bridge Damage Detection Based on Discrete Spatial Wavelet Analysis by Using Ambient Dynamic Loads

利用离散空间小波多分辨分析,分别探讨了匀速简谐汽车作用荷载和随机白噪声作用荷载(模拟汽车与风荷载的耦合)两种环境荷载作用下桥梁已有损伤位置的识别方法。建构了桥梁结构损伤定位的离散空间小波变换的理论模型,同时讨论了不同小波函数的选取及分解层次的确定方法。该方法仅需测量损伤后桥梁的位移或应变响应,不需损伤前后的结构特性,不影响交通。对原始输入的位移信号进行逐步差分前处理使得识别结果更准确。模拟试验表明,离散空间小波多分辨分析是识别环境荷载作用下桥梁损伤位置的准确可靠方法。

This paper presents bridge damage detection technique by using Multi-resolution Analysis of discrete spatial wavelet transform, The investigation is aimed at detecting the damaged location of bridge with ambient dynamic loads （e.g, automobile or stochastic white noise load） , The theoretical models that based on continuous or discrete wavelet analysis of damaged bridge localization are established, and the wavelet selection and the transformation levels are discussed, The method only need the spatially distributed signals （e.g. the displacements or strain or strain mode） and don＇t require modal properties before and after damage, with no impact on traffic. In the method, the stepwise difference technique of the original displacements signals makes the detection results more effective, Simulation experiments show that the spatial wavelet analysis is capable of extracting damage information from the response signal of ambient dynamic loads in a simple, robust and reliable way,