基于希尔伯特变换结构模态参数识别

Modal Parameter Identification of Structures Based on Hilbert Transform

应用HHT方法对GARTEUR飞机模型模态参数进行识别,通过采用多通带滤波器对信号进行滤波,较好的解决模态混叠问题,采用NExT法对信号预处理,由EMD分解获得较准确的各阶固有模态函数分量(IMF),在EMD分解中使用镜像延拓方法对极值点进行处理来抑制端点效应,然后将分解得到的IMF分量进行希尔伯特变换并结合ITD法识别出各阶固有频率和阻尼比。最后对悬臂梁进行数值仿真模拟,并将模态参数识别结果和理论值进行对比,并运用此方法进一步识别GARTEUR飞机模型固有模态参数。

The HHT method is applied to the modal parameter identification of GARTEUR plane model. The multi-channel filter is applied to process the signal for solving the problem of modal aliasing. Meanwhile, the NExT method is adopted to get more accurate individual-order intrinsic mode functions （IMF） form the EMD decomposition. The mirror continuation method is applied to process extreme value points for suppressing the endpoint effect. Then, the natural frequency of each order and the damping ratio are identified with Hilbert transform and ITD method. The numerical simulation of a cantilever beam is carried out and the simulation results are compared with the theoretical results. Finally, the intrinsic modal parameters of the GARTEUR plane model are recognized with this method.