基于Poly IIR方法悬臂梁模态参数识别与研究

Modal parameter identification analysis and study of cantilever beam based on Poly IIR method

该文为研究某风机旋转叶片的断裂原因,利用振动试验台悬臂梁进行类似的振动分析,首先利用弹性体一维振动理论得到悬臂梁的振动数学模型。通过伯努利-欧拉梁理论计算得到悬臂梁振动微分方程,并且对悬臂梁设定与风机叶片相似的边界约束条件计算得到各阶模态参数,利用Workbench有限元仿真分析得到悬臂梁前5阶固有频率与振型,最后用基于Poly IIR算法进行悬臂梁EMA参数识别,得到悬臂梁弯曲与扭转模态频率与振型,验证仿真值、实验值的一致性,可为后续动力旋转机械叶片的设计选型以及结构优化分析提供一定的参考。

In order to study the fracture reason of rotating blade of fan, similar vibration analysis was carried out by adopting vibration table cantilever beam. Firstly, the elastomer one-dimensional vibration theory was used to obtain the vibration mathematical model of cantilever beam. Based on Bernoulli Euler beam theory, the vibration differential equation of cantilever beam was obtained by calculation, and modal parameters of each stage were obtained by setting boundary constraint conditions for cantilever beam that were similar to that of fan blade. Besides, inherent frequency and vibration mode of first 5 stages of cantilever beam were also obtained based on Workbench finite element emulation analysis. Finally, EMA parameter identification of cantilever beam was carried out according to Poly IIR algorithm, and bending and torsion mode frequency and vibration mode of cantilever beam was also obtained, which verified the consistency of simulation value and experiment value, and could provide reference for design and model selection and structure optimization analysis of follow-up power rotating machinery.