基于传递率函数的运行模态分析方法

Transmissibility Based Operational Modal Analysis

传统的运行模态分析方法在推导过程中多假设激励为白噪声,造成在应用上有一定的局限性。提出了一种基于传递率函数的运行模态分析方法,无需采用白噪声假设,利用两种不同载荷情况下的传递率函数构造有理函数,通过有理分式Forsythe正交多项式法对其进行拟合,得到模态频率、阻尼和振型参数。最后,采用机翼模型仿真算例和悬臂梁实验,验证了在非白噪声激励情况下该方法的有效性与可靠性。

Most operational modal analysis algorithms are based on the assumption of white noise excitation,which has some application limitations.A new method utilizing transmissibility functions is presented without the white noise hypothesis.Rational functions(RF)are constructed by combining transmissibility measurements under two different loading conditions,from which modal frequency,damping ratio and modal shapes are obtained by the Forsythe orthogonal polynomial fitting as rational fractions in the frequency domain.Finally,a simulation example of a wing model and an experiment of a cantilever beam are used to validate the method.This technique achieves good results,even if the excitation is not white noise.