采用工作模态识别法进行模态分析

对于一些大型工作结构 ,有时很难测得输入信号 ,只能单独利用实测响应数据进行工作模态识别。本文针对工程实际中的这一情况 ,首先利用响应间互相关函数同脉冲响应函数在表达形式上的相似性 ,推导出了多参考点时域工作模态复指数法 ,继而又从响应间的互相关函数入手 ,推导出了多参考点频域工作模态识别法。最后采用一飞机模型对这两种方法进行了试验验证 ,并将所得结果做了对比分析 ,结果表明 ,两种多参考点方法都能较有效地单独从实测响应数据提取结构的模态参数 ,且频域工作模态识别法比时域工作模态复指数法识别精度更高。

Modal Analysis Using Operating Modal Identification Method

Sometimes it is very difficult for some large-scale operating structures to measure the input forces. Modal parameters must be estimated on response-only. A poly-reference time-domain operating modal identification complex exponential method is presented since cross-correlation functions have the same form as impulse response functions. Then a poly-reference frequency-domain operating modal identification method is proposed in this paper. An experiment on an aircraft model is performed to verify the proposed schemes. The results show that both outlined schemes can extract the parameters from output-only and the modal parameters extracted by proposed frequency-domain method are more accurate than those by presented time-domain complex exponential method.