基于车辆响应的连续梁桥振型识别数值模拟及影响参数分析

Numerical simulation and influence parameter analysis of mode shape identification of continuous beam bridge based on vehicle response

采用过桥车辆振动响应识别桥梁自振特性的间接测量法能够避免传统动载试验测量桥梁振型方法所存在的操作复杂和成本较高等缺点。采用数值模拟的方法,根据车桥耦合振动理论和桥梁振型间接测量法基本原理,对实际工程某连续梁桥建立车辆与桥梁耦合振动的有限元模型,采用双轴半车模型模拟测量车辆,提取车辆匀速通过平整桥面时车辆振动加速度时程响应,并采用带通滤波技术与汉宁窗相结合的处理方法提取分离出与桥梁固有频率相关的桥频分量响应,利用桥频分量响应及其希尔伯特变换构造出与每阶固有频率相对应的振型。采用本方法分析了6种车速、4种社会车辆工况对桥梁振型识别效果的影响特点。数值分析结果表明,车速低于10 km/h以下时高阶振型识别误差较大,车速高于60 km/h以上时振型识别普遍较差,最佳识别车速是30-40 km/h;有社会车辆存在时对桥梁振型识别有利,但是对密集模态识别不利。为推进移动传感间接测量方法在桥梁检测工程中的应用提供理论参考。

Using the indirect measurement method to identify the natural vibration characteristics of Bridges by vibration response of vehicles crossing the bridge can avoid the disadvantages of complicated operation and high cost which exist in the traditional dynamic load test method,The numerical simulation method is adopted,According to the vehicle-bridge coupling vibration theory and the basic principle of bridge indirect measurement method,A finite element model of vehicle-bridge coupling vibration is established for a continuous beam bridge in practical engineering.The two-axis half-car model is adopted to simulate the measuring vehicle.The time-history response of vehicle acceleration when the vehicle passes the bridge at a constant speed is extracted and The response of the bridge frequency component related to the natural frequency of the bridge is separated by combining the band-pass filter with the hanning window.The extracted bridge frequency component response and its Hilbert-Huang transform are used to construct the corresponding mode of each natural frequency.This method is used to analyze the influence of 6 kinds of vehicle speedand 4 kinds of social vehicle working conditions on the vibration pattern identification effect of the bridge.The numerical simulation results show that when the vehicle speed is lower than 10 km/h,the identification error of high-order mode shape is relatively large;when the vehicle speed is higher than 60 km/h,the identification error of high-order mode shape is generally poor,and the best speed identification is 30-40 km/h.In the presence of social vehicles,it is beneficial to identify the high-order mode of the bridge,but unfavorable to the dense mode recognition.It provides some references for promoting the application of indirect measurement method of motion sensing in bridge inspection engineering.