基于Hilbert-Huang变换的结构损伤诊断方法研究

结构物在强震中将产生损伤,其动力特性发生改变,通过对结构瞬时频率的分析可以诊断出结构的损伤发展过程。本文探讨了基于Hilbert-Huang变换的结构物损伤诊断方法,研究了如何从结构地震响应信号中提取模态响应、识别损伤位置和损伤发展规律。采用本文方法分析了三层框架模型,结果表明:带有间歇检验准则的经验模态分解法,能够提取结构的模态振动响应;对比无损伤结构和有损伤结构的Hilbert边际谱,可以诊断出结构损伤的部位;分析模态响应瞬时频率的时变特点,可以直观地掌握振动中结构的损伤发展规律。采用本文方法分析Northridge地震中某建筑物的强震记录,得到了该建筑的损伤发展规律,并证明了此方法的可行性。

Structural damage detection study based on Hilbert-Huang transform

Because the dynamic characteristics of a structure changes if damaged by strong earthquakes,the trend of damage development can be detected by estimating instantaneous frequency.This paper attempts to discuss a new approach to diagnose the structural damage based on Hilbert-Huang transform,as well as analyzes the method of extracting modal responses,detecting damage location and trend of damage development.The numerical results of a three-story frame show that the model responses can be extracted by empirical model decomposition technique with intermittency check criterion,and the damage location can be detected by comparing the Hilbert marginal spectrums of the undamaged structures with those of the damaged ones.Moreover,the trend of damage progress can be accessed by analyzing instantaneous frequency.After analyzing the strong motion data of a building in Northridge Earthquake with the proposed method,the trend of damage development of the building is obtained,demonstrating the feasibility and practicality of proposed method.