移动车辆加载下梁桥挠度影响线识别与损伤诊断方法

为了解决桥梁实测时程响应中存在结构动力成分与车辆多轴效应干扰的问题,提出一种基于挠度影响线识别结果的简支梁桥损伤诊断方法。首先,通过变分模态分解与小波变换法对桥梁时程响应进行预处理,以实现桥梁实测响应动力成分剥离,进而建立多轴车辆信息矩阵和影响线识别模型,从而剔除桥梁实测响应中车辆多轴效应,采用Tikhonov正则化方法识别出桥梁准静态挠度影响线,最后利用影响线差值曲率指标对桥梁损伤进行定位。研究通过两轴和三轴车辆移动加载下的车桥耦合模型验证所提方法的可行性与有效性。研究表明：所提两种影响线识别方法有效、可靠,影响线识别效果受车速和车型的影响较小,其中变分模态分解方法在车辆高速行驶下识别桥梁影响线用于损伤诊断效果更佳。

Deflection influence line identification and damage diagnosis method of beam bridge under moving vehicle loading

In order to solve the problem of interference between structural dynamic components and vehicle multi axial effects in the measured time history response of bridges, a damage diagnosis method for simply supported beam bridges based on the identification results of deflection influence line is proposed. First, the time history response of the bridge is preprocessed by variational mode decomposition and wavelet transform to realize the stripping of the dynamic components of the measured response of the bridge, and then the multi axle vehicle information matrix and the influence line identification model are established, so as to eliminate the multi axle effect of vehicles in the measured response of the bridge. The quasi static deflection influence line of the bridge is identified by Tikhonov regularization method, and finally the influence line difference curvature index is used to locate the bridge damage. The feasibility and effectiveness of the proposed method were verified through a vehicle bridge coupling model under moving loads of two and three axle vehicles. The research shows that the two proposed identification methods of influence line are effective and reliable, and the identification effect of influence line is less affected by vehicle speed and vehicle type, among which the variational mode decomposition method is more effective in identifying bridge influence line for damage diagnosis under high-speed driving.