基于HHT的拉杆转子结构模态参数识别

Modal Parameters Identification of Rod Fastening Rotors Based on HHT

为准确获取航空发动机拉杆转子结构模态特性,应用Hilbert-Huang变换(HHT)方法对结构的模态参数进行识别。首先对结构脉冲响应信号进行带通滤波和经验模式分解(EMD),进而得到结构各阶模态响应信号,然后对信号进行Hilbert变换获取其瞬时特性,最后对瞬时幅值自然对数和相位进行线性拟合,根据拟合结果计算出模态参数,通过与实验值的对比论证了该方法的准确性。

In order to acquire the modal characteristics of rod fastening rotors of aero-engines more accurately,a method based on Hilbert-Huang transform(HHT)is investigated and applied to the identification of modal parameters of the structure.First of all,the band-pass filtering and empirical mode decomposition(EMD)are performed for the response signal measured under impulsive excitation to obtain the modal response signals of different orders of the structure.Then,the Hilbert-Hwang transform(HHT)is applied to obtain the instantaneous characteristics of each modal response.Finally,the least-square linear fitting technique is employed to get the linear relation between the natural logarithmic of the instantaneous amplitude and the phase.According to the results of the linear fitting,the modal frequency and damping are extracted.Comparison of the results with those of experimental modal analysis shows that the HHT method is applicable to modal parameters identification of aero-engine rod fastening rotors.