单帧FFT法在正弦扫描结构动特性试验数据处理中的应用

摘要

在正弦扫描结构动特性试验中，当扫描速率过快时，传统的Hilbert法和同相正交分解法处理结果误差较大。针对上述缺点，采用了单帧 FFT 法，并通过单自由度理论仿真算例和试验对方法进行验证。研究表明单帧 FFT 法具有更好的精度，处理结果的频率和幅值受试验扫描速率影响小，且没有“旁瓣效应”，是一种更为有效的正弦扫描结构动特性试验数据处理方法。%In sine swept structure dynamics test, progressing results of Hilbert method and Co- phased-Quad-Orthogonal-Decomposed method had bigger error when sweeping rate was too rapid. Single frame FFT method was used against the shortcomings of the above. A single freedom numerical example and experiment were actualized to validate the single frame FFT method. The research indicates that single frame FFT method has higher precision, frequency and magnitude of processed result are affected little by sweeping rate, and processed results do not have side lobe effect. Single frame FFT method is more available in sine swept structure dynamics data processing.