桥梁结构全息模态参数识别方法试验研究

针对传统桥梁结构健康监测中使用的接触式传感器存在数据离散性大、安装程序繁琐、难以反应桥梁结构整体状况等局限性,本文基于全息视觉传感器智能监测系统,识别结构全息几何形态在相应时空域上的振动信号,较为准确的获取结构全息图像数字化位移坐标信息,同时针对提取的振动位移进行频谱分析,获取桥梁结构的模态参数,实现对桥梁状况的基本识别。本文对一座缩尺模型桥进行试验验证,研究结果表明：全息视觉传感器智能监测系统测试结果与位移传感器测试结果吻合度较高,针对竖向荷载响应的功率谱,两种方法实测结果在低频范围内都能够较好地吻合,振型变化趋势基本一致。基于全息视觉传感器智能监测系统的桥梁形态监测真实、连续、敏感,较为准确地反映了结构在各工况下的位移变化和模态响应,后期将会进一步优化全息视觉传感器监测系统识别灵敏度,实现在各种工况激励下的高阶模态参数和结构损伤识别。

Experimental Study on Holographic Modal Parameter Identification of Bridge Structures

Aiming at the limitations of traditional contact sensors used in bridge structure health monitoring, such as large discreteness of data, cumbersome installation procedure and difficult to reflect the overall situation of bridge structure, an intelligent monitoring system based on holographic vision sensor was developed to recognize the vibration signals of the holographic geometry in the corresponding time and space domain, and obtained the digital displacement coordinate information of the hologram image of the structure accurately. Meanwhile, the spectrum analysis of the extracted vibration displacement was carried out to obtain the modal parameters of the bridge structure and realized the basic identification of the bridge condition. In this paper, a scaled model bridge was tested and verified. The results show that the test results of the intelligent monitoring system based on holographic vision sensor are in good agreement with the test results of the displacement sensor. For the power spectrum of the vertical load response, the test results of the two methods are in good agreement in the low frequency range and the mode shape change trend is basically the same. Bridge shape monitoring based on holographic vision sensor intelligent monitoring system is real, continuous and sensitive, which can accurately reflect the displacement change and modal response of the structure under various working conditions, and holographic vision sensor can realize the holographic display of the structure displacement. In the later stage, the recognition sensitivity of the holographic vision sensor monitoring system will be further optimized to realize the high-order modal parameters and damage identification under various excitation conditions.