基于改进HHT的结构损伤识别方法研究

发布时间：2018-05-01 12:11

本文选题：损伤识别 + 镜像闭合延拓　；参考：《长沙理工大学》2014年硕士论文

【摘要】：随着经济实力和科学技术的飞速发展,高层建筑在我国如雨后春笋般拔地而起。高层建筑结构在长期使用过程中的健康和安全也越来越受到人们的关注,结构损伤识别以及结构健康监测已经成为现在工程界热门研究方向。本文首先对结构损伤识别的方法以及国内外的研究现状进行综述,并重点对Hilbert—Huang变换方法(HHT)进行了介绍。HHT方法是一种全新的、自适应的时频分析方法,因其在处理非线性、非稳态信号方面的优良特性,被广泛运用到众多领域的研究中。由于Hilbert—Huang变换理论尚未在数学上得到严格意义上的证明,其算法自身也存在一定的缺陷,进而影响到了其对模态参数的识别。本文对HHT方法中存在端点效应和模态混叠问题以及对参数识别造成的影响进行了分析,阐述了利用镜像闭合延拓抑制端点效应以及利用总体平均经验模态分解抑制模态混叠的方法。通过数值算例证明了镜像闭合延拓和总体平均经验模态分解的在抑制端点效应以及模态混叠问题方面的有效性。将改进的Hilbert—Huang变换应用到地震作用下结构损伤的识别中。建立了一个三自由度剪切型刚度退化模型,利用改进的Hilbert—Huang变换对该模型在不同强度地震作用下的响应进行分析,通过结构瞬时频率的变化对结构是否出现损伤进行识别,提出了一阶固有模态函数(IMF)能量识别损伤位置的方法。将改进的HHT方法应用到对实际工程的健康监控数据的分析中,对某办公楼建筑在Northridge地震中获得的地震响应进行HHT分析,通过瞬时频率以及一阶IMF能量变化规律识别了该建筑在地震中发生损伤的情况,证明了改进的Hilbert—Huang变换在实际应用中的实用性。
[Abstract]:With the rapid development of economic strength and science and technology, high-rise buildings have sprung up like bamboo shoots after the rain in China. The health and safety of high building structures are becoming more and more popular in the process of long-term use. Structural damage identification and structural health monitoring have become a hot research direction in the engineering field. The method of structural damage identification and the current research status at home and abroad are reviewed, and the Hilbert Huang transform method (HHT) is introduced. The.HHT method is a new and adaptive time-frequency analysis method, which is widely used in the research of many fields because of its excellent characteristics in dealing with nonlinear and unsteady signals. The Hilbert Huang transformation theory has not been proved in the strict sense of mathematics, and its algorithm itself has some defects, and then it affects its identification of modal parameters. This paper analyzes the existence of endpoint effect and modal aliasing and the influence on parameter identification in the HHT method, and expounds the use of the mirror image. The closed extension suppresses the endpoint effect and uses the overall mean empirical mode decomposition to suppress the modal aliasing. Through numerical examples, the effectiveness of the mirror closed extension and the overall mean empirical mode decomposition in the suppression of endpoint and modal aliasing problems is proved. The improved Hilbert Huang transformation is applied to the earthquake action. In the identification of lower structural damage, a three degree of freedom shear type stiffness degradation model is established, and the modified Hilbert - Huang transformation is used to analyze the response of the model under different intensity earthquakes. The first order inherent modal function (IMF) can be identified by the change of the instantaneous frequency of the structure to identify the damage of the structure. The modified HHT method is applied to the analysis of the health monitoring data of the actual project. The seismic response of an office building in the Northridge earthquake is analyzed by HHT. The damage of the building in the earthquake is identified by the instantaneous frequency and the law of the first order IMF energy change. The practicability of the improved Hilbert - Huang transform in practical application is given.

【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU317

【参考文献】