温度变化下基于固有频率聚类分析的空间网格结构损伤诊断  

Damage Diagnosis of Space Grid Structure Based on Natural Frequency Clustering Analysis under Varying Temperature Effects

作　　者：韩庆华[1,2,3] 马乾 刘名 徐杰[1,2,3] Han Qinghua;Ma Qian;Liu Ming;Xu Jie(Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China Earthquake Administration,Tianjin University,Tianjin 300350,China;Key Laboratory of Coast Civil Structure Safety of the Ministry of Education,Tianjin University,Tianjin 300350,China;School of Civil Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学中国地震局地震工程综合模拟与城乡抗震韧性重点实验室,天津300350 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300350 [3]天津大学建筑工程学院,天津300350

出　　处：《华东交通大学学报》2021年第4期8-17,共10页Journal of East China Jiaotong University

基　　金：国家自然科学基金联合基金项目(U1939208);高等学校学科创新引智计划资助项目(111计划-B20039)。

摘　　要：固有频率是损伤诊断方法提取的主要动力特征之一,其不仅与结构本身刚度有关,还极易受温度等环境因素的影响。提出了一种环境温度变化下基于固有频率聚类分析的空间网格结构损伤诊断方法。首先对结构固有频率的环境温度影响原理进行了公式推导,据此以一网架结构为研究对象,模拟了温度变化与损伤共同作用下的固有频率数据;进而对固有频率进行主成分分析(PCA),提取主成分重构残差进行模糊c均值聚类(FCM),实现结构损伤诊断。研究结果表明:环境温度通过引起热变形、改变材料特性和产生温度内力对固有频率产生影响;固有频率随温度变化的日常波动,将直接影响损伤的准确诊断,通过PCA-FCM聚类分析可在损伤诊断过程有效排除环境温度因素干扰,在健康基线未知情况下对损伤是否发生进行判别,并能对损伤程度进行准确识别。Natural frequency is one of the main dynamic characteristics of damage diagnosis methods,which is not only related to the stiffness change of the structure itself,but also easily affected by environmental factors such as temperature.A natural frequency clustering analysis method is proposed,which is used for damage diagnosis of space grid structure under environmental changes.First,the influence of the natural frequency of the structure on the environmental temperature is derived.based on this analysis,a grid is used as the research object to simulate the natural frequency data under the condition of temperature changes and damage;then the principal component analysis(PCA)of the natural frequency is developed,and the structural damage diagnosis was realized by using fuzzy c-mean(FCM)clustering based on principal component reconstruction residuals.The research results show that the ambient temperature affects the natural frequency by causing thermal deformation,changing the material properties and generating temperature internal forces;the daily fluctuation of the natural frequency with temperature will directly affect the accuracy of damage diagnosis,and the PCA-FCM clustering can be used in the damage diagnosis process which can effectively eliminate the interference of environmental temperature factors,judge whether the damage occurs when the health baseline is unknown,and accurately judge the degree of damage.

关 键 词：固有频率 温度影响 空间网格结构 损伤诊断 主成分分析 模糊C均值聚类 

分 类 号：TU311.4[建筑科学—结构工程]