等角度重采样在航空发动机振动分析中的应用

Application of Equal Angle Resampling Method in Aircraft Engine Vibration Analysis

航空发动机在工作中存在稳态与非稳态两种状态,当发动机处于稳态时,采用短时傅立叶方法即可对发动机振动数据进行分析,但是如果发动机处于过渡态,发动机转速随时间快速发生变化,此时采用短时傅立叶对发动机振动数据进行分析会存在很多问题,如果分析数据段选择过长,该时间段内发动机转速已经不是均匀转速,直接导致分析结果错误,如果分析时间过短,则傅立叶分辨率过低,计算结果不准确。针对以上问题,提出采用等角度重采样方法对航空发动机过渡态振动数据进行分析,可以比较准确的分析出发动机转速频率对应的振动值。

There are steady state and non-steady state during operation process of the aircraft engine ; when the engine is on the steady state, the short time Fourier transformation method could be utilized to analysis the engine vibration data, but if the engine is on the transition state, the engine rotation speed changes fast over time, and the short time Fourier transformation method would bring some problems if it is still be utilized there. Because if the analysis data segment is selected too long, the rotation speed of the engine which is not uniform speed would lead to wrong analysis results ; while if the analysis data segment is selected too short, the resolution rate of Fourier transformation method is too low, which would still lead to wrong result. In view of the above problems, this article presents an equal angle and repeated sampling method to analyze the transition state engine vibration data. This method could analyze the vibration value according to the corresponding engine rotation speed more accurately.