基于结构高阶局部模态的损伤诊断研究

结构振动测试和损伤诊断中,较易得到结构的低阶模态信息,但低阶模态信息主要反映结构的整体性能,对结构局部损伤不敏感.本文主要研究框架结构高阶模态特性,并通过高阶模态来反映结构的局部特征,实现框架结构损伤诊断.研究中采用理论模态分析和实验模态分析相结合的方法.理论模态分析表明框架结构存在模态密集区且高阶模态具有局部特征.采用局部激振方法对一个钢筋混凝土框架结构模型施加激励,通过实验模态分析获取高阶局部模态信息.结果表明最大能量高阶模态可以识别框架柱的刚度变化.

Research on structural damage diagnosis based on structural high order local modes

In structural dynamic testing and damage detection,the low-order modal information of a structure can be easily obtained,which reflects mostly the global behavior of the structure rather than the local characteristics of the structure.By using the theoretical and experimental modal analysis,this paper investigated the high-order modal properties of the frame structures and the relationship between the high-order modal parameters and the local characteristics of the frame structures in order to implement damage diagnosis of the structures.The theoretical modal analysis showed that there was a dense high-order mode section and the high-order modes behaved the local characteristics in the frame structures.A local exciting method was used to obtain the high-order modes information on a reinforced concrete frame model by the experimental modal analysis method.It was known from the testing results that the stiffness change of a column in the frame structures could be detected by the maximum energy high-order modes.