用互功率谱进行未知激励下的模态振型识别

在激励满足白噪声的假设下，可以将互相关函数代替脉冲响应函数用于多参考点最小平方复指数法，单独利用响应数据求出系统的自然频率和阻尼，但元法获得模态振型。该文提出卫和种用互动率谱求振型的方法，并对此理论进行了详细推导，以一悬臂梁为例对该方法进行了试验验证。结果表明，采用该方法能够有效地识别出模态振型，从而 弥补了复指数法在未知激励下进行模态分析的不足。

Identification of Mode Shape by Fitting Cross-power Spectra under Unknown Excitation

The cross correlation functions is applied to PRCE method to extract the natural frequencies and damping from output only under the white noise excitation,but the mode shape can't be determined. This paper gives a theoretical formulation for the extraction of mode shape by fitting the cross power spectra of the outputs and a cantilever beam is analysed. The results show that the present method can identify the mode shape accurately and complement the use of PRCE under unknown excitation condition.