Abstract: Considering that periodic excitation normally exists in running machine the effects of periodic excitation on modal analysis results were studied by using numerical simulation. Through extracting the amplitude curve diagram from correlation function of response of the structure the modal components of harmonic response could be directly identified and the interference of periodic excitation elimilated by digital filtering technique The results of simulation test show that periodic excitation could be identified accurately by this method. This is of value in operational modal identification of linear stationary system.

Key words: vibration and wave , operational modal , modal amplitude curve , non-stationary , periodic excitation

摘要：  针对运行机械中通常存在周期激励这一情况，应用数值仿真的方法，研究周期激励对模态分析结果的影响。通过提取结构响应相关函数的模态幅值曲线图，能直观的识别出周期谐波响应模态成分，然后应用数字滤波技术滤除周期激励的干扰。仿真及试验结果表明该方法能够准确的识别出周期激励，对线性定常系统的工作模态分析具有一定的参考价值。

关键词: 振动与波, 工作模态, 模态幅值曲线, 非平稳, 周期激励