基于提升小波变换和统计理论的简支梁桥损伤识别分析

Damage Identification Analysis of Simply Supported Beam Bridge based on Lifting Wavelet Transform and Statistical Theory

为了解决损伤识别中对健康结构响应数据的依赖问题和小损伤难以识别情况,提出基于提升小波变换和统计理论的简支梁桥损伤识别分析方法,通过测得损伤状态下的动态应变响应即可对损伤位置直接判断。首先基于应变响应对结构局部损伤的敏感性,利用提升小波变换分解重构出比原始应变响应更加光滑的低频应变响应;然后根据统计理论,构建出应变方差局部概率(Strain Variance Local Probability,SVLP3)损伤指标进行损伤定位分析。以简支梁桥为研究对象,在数值模拟中讨论了单处、多处损伤、不同车速与荷载、抗噪性以及测点稀疏布置等方面对损伤识别效果的影响;最后通过简支梁桥模型进行了实验验证,结果表明所提方法在简支梁桥损伤识别中简单有效,对微小损伤也能准确识别。

In order to solve the problem of dependence on health structural response data in damage identification and the difficulty of identifying small damage,a new damage identification method for simply supported beam bridges based on lifting wavelet transform and statistical theory is proposed,which can directly identify the damage location by measuring the dynamic strain response in the dam‑age state.Firstly,based on the sensitivity of the strain response to the local damage of the structure,the lifting wavelet transform is used to reconstruct the low-frequency strain response which is smooth‑er than the original strain response;And then according to the statistical theory,the damage index of strain variance local probability(SVLP3)is constructed for damage location analysis.Taking a simply supported beam bridge as the research object,it discusses the effects of single damage,multiple dam‑age,different speed and load,the noise resistance and the sparse measuring points in the numerical simulation.Finally,the experimental verification is carried out by the model of simply supported beam bridge,and the experimental results show that the proposed method is simple and effective in the dam‑age identification for simply supported beam bridge and can also accurately identify minor damage.