SPECTRAL ANALYSIS OF VIBRATION SIGNAL USING FOURIER TRANSFORM

Abstract

The paper analyzes the topical issue of timely detection and prevention of a dangerous state of critical machines and mechanisms using vibration diagnostics as a promising method. It is proposed to use the method of analysis of vibration spectra in order to identify malfunctions, by processing the output signal from the sensor, which is sent to a personal computer, where a spectral analysis of the measured vibration signal is performed using a diagnostic program based on MATLAB. It is proposed to use spectral analysis, which is a traditional method of vibration diagnostics. It is supposed to determine the faulty state according to vibration measurement data and then to determine the nature of the fault according to the vibration signals analysis using the Fourier transform. It is proposed to process the output signal from the vibration sensor to a personal computer, where a spectral analysis of the measured vibration signal is carried out using a diagnostic program based on MATLAB. The use of FFT algorithms is due to a decrease in the number of operations performed, and, consequently, an increase in performance. It is shown that the decomposition of a complex signal in a Fourier series gives the components of the spectrum, which are, in narrow-band analysis, the harmonic components of the complex signal. It has been determined that narrowband spectral analysis allows detecting a larger number of faults or defects and is used for monitoring and in-depth diagnostics of equipment. Knowing the frequencies at which malfunctions of the kinematic pairs of machinery are manifested, the amplitude of the spectrum components can be used to assess their state. It was determined that spectral analysis is widely used in the processing of vibration diagnostics data, being the main and classical method of analysis. To optimize the duration of the test, it is necessary to take into account the relationship between the spectrum bandwidth and the signal accumulation time. The pass-through characteristic reflects the dependence of the signal level on time at a certain frequency, illustrating the process of signal accumulation during narrow-band spectral analysis. The narrower the analysis strip, the longer the measurements take.