HHT法识别结构模态频率和阻尼比的改进

Improvement on HHT method for identifying modal frequency and damping ratio of structure

在应用EMD方法分解信号时,可能造成固有模态函数中不同的振动模态混合,从而淹没能量较小的振动模态而导致无法识别其模态参数。为了提高结构模态参数识别的精度和比较精确地识别低频模态及能量较小模态的参数,文章对结构响应信号进行带通滤波后再应用EMD方法进行分解,最后得到结构的各阶模态频率和阻尼比;仿真结果表明,该方法可以有效提高结构模态频率和阻尼比的识别精度。

There are possibilities that the different vibration modes are mixed in intrinsic mode functions（IMFs） while carrying out Empirical Mode Decomposition（EMD）,with the result that it is impossible to identify the modal parameters of those submerged lower-energy modes.To increase the precision of the structural modal parameters and to more precisely identify modal parameters of low-frequency and lower-energy modes,bandpass filters are adopted to process the response signals in this paper,then the EMD is applied to the filtered signals,and the modal frequency and damping ratio of structure are obtained. The simulation results demonstrate that the method given in the paper can effectively improve the identification precision of modal frequency and damping ratio of structure.