【作者】 李大军；

【导师】 霍达；

【作者基本信息】 北京工业大学 ， 结构工程， 2005， 博士

【摘要】 基于振动的损伤识别方法将振动的外界因素作为激励源,损伤检测的过程不影响结构正常使用,能方便地完成结构损伤的检测和识别,是桥梁整体检测的主要方法。随着基于环境激励下结构模态参数识别方法的进展、传感器性能的增强,环境激振正在成为大型桥梁结构检测的主要激振方式。但桥梁结构较多的不确定因素、复杂的工作环境以及大型性导致的结构的动力特性测量精度低、损伤定位因子灵敏度低以及结构早期信息不完备限制了工作状态下桥梁损伤检测方法在实际工程中的应用。本文在系统总结了近年来结构损伤识别领域比较成熟的方法和新的研究思路基础上,进行了针对随机激励下桥梁结构损伤识别方法的研究,具体研究内容如下: (1) 随机激励下桥梁结构的模态参数识别方法研究考虑到在结构的所有模态参数中,固有频率是最容易获得也是精度最高的一个,本文提出了一种利用移动质量块在不同位置时对桥梁进行多次测量,只利用各次测量的频率值来确定桥梁结构损伤的新的桥梁损伤检测方法-移动质量多次检测法,并推导出了由移动质量多次检测的模态频率表达位移模态的公式,从而给出了一种随机激励下桥梁位移模态识别的新方法,这种方法提高了结构位移模态的识别精度,使其接近于模态频率的识别精度。同时,桥梁的移动质量检测法实现了只由结构的低阶模态频率甚至一阶模态频率确定桥梁损伤的目标,提供了一种工作状态下桥梁实际检测的简便方法。(2)工作状态下桥梁损伤定位方法研究在工作状态下进行桥梁损伤定位时,模态参数的不完备是不可避免的同时也是造成损伤定位困难的主要原因,因此本文研究了在不完备模态参数条件下桥梁损伤位置的识别方法。在基于单元模态能变化的损伤定位方法的基础上提出了损伤定位的单元弯曲模态应变能法,在柔度曲率法的基础上提出了柔度差更多还原

【Abstract】 Vibration-based damage identification method is the leading method of nondestructive testing technique in bridge structure. As the development of mode identification methods and the capability of sensor, ambient excitation is becoming the mostly way of excitation. But the application of damage detection method based on ambient excitation is limited because of the low precision of dynamic parameter measurement and imperfection of early structural information. Base on the present research, the research works is explored and developed deeply for damage detection method of bridge structures based on ambient excitation in this paper, and research works on 4 aspects have been done around the purpose. (1)Study on mode identification of bridge structure based on ambient excitation Consider the practicability of damage detection, the damage identification of bridges ought to be based on ambient excitation. So, the modal analysis based on ambient excitation is very important for damage identification of bridges. In this paper, a new modal analysis and damage identification method is developed for bridge structures, in which the displacement mode and curvature mode can be obtained by nature frequency and so local damage are characterized by only the nature frequency measured from the damaged structures, in contrast with most of the existing vibration-based damage identification methods, which require both the nature frequency and other modal parameters measured from the damaged structure. By the method proposed in this paper, the displacement mode can be obtained as the same exactitude as nature frequency, contrast with most of the existing modal analysis method, in which the exactitude of displacement mode obtained from testing data is much lower than that of nature frequency. (2)Study on damage localization based on ambient excitation It is hard to localize the damage on operating condition because of the modal data can not be obtained completely. Based on the modal flexibility of field observation, a damage localization approach is developed for the bridge structure in this paper, in which damage is更多还原