基于车-桥响应连续小波变换的桥梁无模型损伤识别方法  

A Bridge Model-free Damage Identification Method Based on Continuous Wavelet Transform of Vehicle-bridge Response

作　　者：安宁 和海芳[1] 马瑞[1] 蔺宝垚 AN Ning;HE Hai-fang;MA Rui;LIN Bao-yao(Research Institute of Highway,Ministry of Transport,Beijing 100088,China)

机构地区：[1]交通运输部公路科学研究院,北京100088

出　　处：《公路交通科技》2022年第8期25-31,共7页Journal of Highway and Transportation Research and Development

基　　金：中央级公益性科研院所基本科研业务费项目(2021-9053a,2021-9053b)。

摘　　要：与传统的基于桥梁动力响应的桥梁损伤识别方法不同,提出了一种基于车辆-桥梁耦合振动时程连续小波变换的桥梁结构无模型损伤识别方法。以简支梁为例,假定桥梁的损伤形式为裂缝,并使用集中扭转弹簧来模拟梁中的裂缝,进而利用传递矩阵法,确定了损伤简支梁的模态参数、固有频率和振型。使用弹簧-阻尼-质量系统模拟车辆,建立了简支梁在移动弹簧质量单元作用下的车辆-桥梁耦合振动模型,并推导了车辆-桥梁系统的运动方程,利用模态分解理论得到了简支梁和移动弹簧质量单元的振动响应。根据桥梁裂缝的数量、位置和深度设置了5种不同工况,使用Mexican Hat小波分别对车辆和桥梁的竖向位移时程进行连续小波变换,找到小波系数取极大值的点,即信号的突变点,从而确定了桥梁的损伤位置。对振动响应添加5%的噪声后,使用连续小波变换方法仍然能清晰分辨出变异点的位置,但当裂缝位于桥梁端部时,可能会造成误判。为了解参数对识别结果的影响,分别按照车辆速度、车辆质量、车辆刚度等参数共设置了15种不同工况,进行识别效果的比较。结果表明:该方法能够准确确定损伤位置,是一种有效的方法;当车辆较重、车速较低时的桥梁损伤识别效果较好,而车辆的刚度和阻尼对桥梁损伤识别结果的影响较小。Different from the traditional bridge damage identification method based on bridge dynamic response,a model-free damage identification method for bridge structures based on continuous wavelet transform of vehicle-bridge coupling vibration time-history is proposed.Taking simple supported beam for example,assuming that the damage form of the bridge is cracks,and a concentrated torsion spring is used to simulate the cracks in the beam,then the modal parameters,natural frequency and mode shape of the damaged simple supported beam are determined by the transfer matrix method.Using the spring-damping-mass system to simulate the vehicle,the vehicle-bridge coupling vibration model of the simple supported beam under the action of the moving spring-mass element is established,the motion equation of the vehicle-bridge system is derived,and the vibration response of the simple supported beam and moving spring-mass element are obtained by using the modal decomposition theory.According to the number,location and depth of bridge cracks,5 working conditions are set,the continuous wavelet transform on the vertical displacement time histories of the vehicle and the bridge are performed respectively by using the Mexican Hat wavelet,and the point where the wavelet coefficient takes the maximum value(the signal mutation point) is found,thus the damage location of the bridge is determined.After adding 5% noise to the vibration response,the position of the variation point can still be clearly identified by using the continuous wavelet transform method,but when the crack is located at the end of the bridge,it may cause misjudgment.In order to understand the influence of parameters on the identification result,a total of 15 working conditions are set according to the parameters such as vehicle speed,vehicle mass,and vehicle stiffness,etc.to compare the identification effects.The result shows that(1) the method can accurately determine the damage location and it is an effective method;(2) the bridge damage identification effect is better

关 键 词：桥梁工程 损伤识别 小波变换 梁桥 车-桥耦合振动 扭转弹簧模型 

分 类 号：U446.2[建筑科学—桥梁与隧道工程]