基于运行模态分析的典型结构模态研究

Typical structural modal research based on operational modal analysis

随着结构的大型化以及激励的复杂化,难以通过传统的实验模态分析法得到结构的模态参数。本文基于自然激励法(NExT)和特征系统实现法(ERA)建立NExT-ERA模态识别理论,提出新的模态分析方法,识别自由板的模态参数。同时对自由板进行单点激振器激振,多点响应测量的模态分析试验,并对比自由板Ansys仿真分析、实验模态分析和NExT-ERA模态分析的识别结果。结果显示,NExT-ERA模态分析方法在频率、振型识别上具有良好的识别精度,也能准确识别实验模态分析中缺失的模态。

The model parameters of the structure are identified using the response signals generated by the structure's own excitation in the operating condition.Based on the natural excitation technique(NExT)and eigensystem realization algorithm(ERA),the NExT-ERA theory is proposed to identify model parameters of the free plate.Modal analysis experiment is conducted with single-point shaker excitation and multi-point response measurement on the free plate.And the results obtained from simulation analysis,modal analysis experiment and NExT-ERA method are compared.Compared with the result of simulation analysis,experimental analysis,it shows that Next-ERA modal analysis method has a good accuracy on frequency and modal shape.And it also has an excellent recognition effect on the mode which is missing in the result of experimental modal analysis.The modal frequency and model shape can be identified effectively with Next-ERA modal analysis method.