一种环境激励下斜拉桥模型损伤识别方法

One Damage Identification Method of a Cable-stayed Bridge Model in Natural Excitation Environment

虚拟脉冲响应函数可表征环境激励下结构系统固有的动力特性,但桥梁试验模型空间变异的模糊性和测量过程中环境激励的随机性,使得虚拟脉冲响应函数同时具有随机不确定性和模糊不确定性,适用于随机-模糊统计原理处理.而Hilbert-Huang变换(HHT)是一种新的适用于非线性、非平稳信号且具有自适应性的数据处理方法.提出了基于HHT与虚拟脉冲响应函数随机模糊均值的结构损伤识别方法,并将4个Hilbert边际谱能量指标应用到室内斜拉桥模型的损伤识别中.结果表明:主梁损伤前后4种能量指标都发生了变化,且体现出相似的规律性,准确指示了较大程度损伤的损伤位置和程度,为大型桥梁结构在线监测提供了一种方法.

Virtual impulsive response function can represent the natural dynamic characteristics of the structure system in natural excitation environment.But fuzzy characteristics of the spatial variation of bridge test model and random characteristics of natural excitation in measuring process render virtual impulsive response function possessing both random uncertainty and fuzzy uncertainty,which can be disposed by random-fuzzy statistics principle.HHT is a novel data analysis method which can be used in nonlinear non-stationary data and it's very adaptive.The method of HHT combined with virtual impulsive response function random-fuzzy mean was proposed to distinguish structural damage,and four Hilbert marginal spectrum energy index were applied to the damage identification in indoor cable-stayed bridge model.The results indicated that four Hilbert marginal spectrum energy index all changed before and after girder damaged,manifesting an analogical trend,bigger damaged location and extent could be indicated accurately,and a way for the large bridge online monitoring system was provided.