中文摘要：

针对机械系统固有频率和阻尼比的识别问题,提出了基于经验模式分解（EMD）的模态参数识别方法。该方法首先对脉冲激励下机械系统的位移响应进行了EMD分解,确定与该系统的各阶模态对应的固有模式函数（IMF）,分别对各阶IMF进行希尔伯特变换以得到各自的瞬时幅值和瞬时相位曲线,并对所得曲线进行线性拟合,最后根据拟合曲线的参数来识别模态固有频率和阻尼比。以简支梁为研究对象,利用EMD方法对其瞬态动力学响应进行了模态参数识别。研究结果表明,使用EMD方法对此类系统进行模态分析具有较好的效果。

英文摘要：

In order to indentify the modal parameters of the mechanical systems,a modal parameter identification method based on the empirical mode decomposition（EMD） was investigated.The EMD method was employed to decompose the vibration signals of a mechanical system under impulsive excitation.Different modal components with lower orders were picked up,and then the Hilbert transform was applied to identify their natural frequencies and damping ratios from the intrinsic mode functions（IMF）.The modal analysis by ANSYS was firstly performed on a simply supported beam.Then,an arbitrarily chosen transient dynamical response of the system was decomposed and the modal parameter was identified by the EMD method.Comparisons between the results from the theoretical predictions,the ANSYS and the EMD show that,the EMD method can be used to perform the modal analysis of such system effectively.