振动响应传递率的动力学特性研究及其在工作模态分析中的应用

Dynamic characteristics of vibration response transmissibility and its application in operational modal analysis

振动响应传递率描述了多自由度系统中各自由度响应之间的关系,近年来在多个领域得到了广泛的应用,特别是在工作模态分析方面,获得了瞩目的应用成果。但对于振动响应传递率的动力学特性,一直缺乏完整的、系统的分析。为此,将从振动响应传递率的基础概念出发,对不同输入情况下,振动响应传递率在系统零极点的特性和对系统输入的依赖性进行解析推导分析;然后,通过数值算例对振动响应传递率的特性进行仿真验证;最后,应用振动响应传递率对非白噪声激励下梁结构的工作模态进行了辨识,表明基于振动响应传递率的工作模态分析方法能够避免虚假模态对辨识结果的影响。

Vibration response transmissibility describes relations among responses of various DOFs in a multi-DOF system. It is widely applied in many fields and achieves remarkable application results, especially, in the field of operational modal analysis. But, there is a lack of complete and systematic analysis for dynamic characteristics of vibration response transmissibility. Here, starting from the fundamental definition of vibration response transmissibility, under different inputs, features of vibration response transmissibility at zeros and poles of a vibration system and its dependence upon the system input were deduced and analyzed analytically. Then, numerical examples were taken to simulate and verify vibration response transmissibility’s these characteristics. Finally, the vibration response transmissibility was applied to identify operational modes of a beam structure under non-white noise excitations. The results showed that the operational modal analysis method based on the vibration response transmissibility can avoid influences of false modes on its recognition results.