A review of spectral analysis for low-frequency transient vibrations

Abstract

The precision tools equipped with active vibration isolation platform in high-tech facilities are sensitive to low-frequency vibration. Currently, there are neither standards nor rules to select the time period of vibration data for conducting the spectral analysis of low-frequency vibration, and none of the analyses can be used to compare and discuss the differences of spectral amplitude generated by the selection of different time periods. Therefore, to estimate the amplitude of low-frequency vibration, the spectral analysis at low-frequency range is crucial. This paper is to elaborate the spectral analysis procedures on various band widths by using zero-padding on the vibration signal in low-frequency band. The mechanism not only facilitates to obtain more reliable result but also to lay a common base for comparison from different user. Finally, the in situ measurement data, including high-speed train-induced low-frequency vibration, are used to exemplify the length of time period affects the results of spectral analysis, either on narrowband or one-third octave band analysis.