利用有限振动响应快速反演时变荷载的方法与试验  

A method and experiment of rapid identification of time-varying load using limited vibration response

作　　者：项子儒 王轶 钱王苹 顾镇媛 XIANG Ziru;WANG Yi;QIAN Wangping;GU Zhenyuan(School of Transportation and Civil Engineering,Nantong University,Nantong 226019,China;MOE Key Lab of Disaster Forecast and Control in Engineering,Jinan University,Guangzhou 510632,China)

机构地区：[1]南通大学交通与土木工程学院,江苏南通226019 [2]暨南大学重大工程灾害与控制教育部重点实验室,广州510632

出　　处：《振动与冲击》2022年第12期275-282,292,共9页Journal of Vibration and Shock

基　　金：江苏省高等学校自然科学研究面上项目(20KJD560002);国家自然科学基金(51808298);南通市基础科学研究项目(JC2020124)。

摘　　要：移动荷载是影响桥梁使用寿命的主要因素之一,对其准确地监测与识别能为桥梁养护提供重要依据。基于振动响应反演的移动荷载识别研究经过五十多年的发展,形成了以时域法、频时域法为主的多种方法,取得了不错成就。然而在解决该类方法面临的主要问题:计算耗时明显、反问题求解病态上,现有技术大多需要使用多项测点和复杂优化,在实际工程应用中并不友好。在时域反卷积法和荷载形函数法的基础上,定义新的构造矩阵提取系统矩阵中的有效元素进行荷载识别,在保障对大噪声的鲁棒性的同时,使测点数量和计算成本进一步降低。在数值仿真算例中,该方法在使用含10%和20%白噪声的动挠度响应情况下,仍能稳定地识别周期性移动荷载,除荷载上、下桥阶段,并未出现明显的奇异性。在试验验证中,利用两个试验分别验证了该方法对集中荷载、移动荷载的识别,其精度与计算效率均可满足实际工程需求。Moving force is one of the main factors that affect the service life of bridges.Accurate identification of moving force can provide an important basis for bridge maintenance.Over the past five decades,the research on moving force identification has formed a variety of methods based on the time-domain method and the frequency-domain method,and has made great achievements.However,in order to solve the problems such as time-consuming and ill conditioned,most of the existing technologies need to use multiple measuring points and complex optimization,which are not friendly in practical applications.Based on the time domain deconvolution method and the load shape function method,a new construction matrix was defined to extract the effective elements of the system matrix for force identification,which can guarantee the robustness to large noise,and further reduce the number of measuring points and the calculation cost.The numerical simulation shows that the method identifiesthe moving force on a simply supported beam with good stability and accuracy,even using a single dynamic deflection response with 20%white noise.The proposed method has also been verified with 2 experiments,both point force and moving force are successfully determined,the accuracy and calculation efficiency can meet the engineering requirements.

关 键 词：移动荷载识别 时域法 桥梁健康监测 

分 类 号：U441.2[建筑科学—桥梁与隧道工程] U446.1[交通运输工程—道路与铁道工程]