A comparative study on damage detection in speed-up and coast-down process of grinding spindle-typed rotor-bearing system

In this paper, the damage detection from non-stationary mechanical vibration signals collected during acceleration and deceleration was performed. A laboratory grinding spindle-typed rotor-bearing system was equipped, and modal testing was carried out to identify system characteristics and operating range. Time–frequency analysis method such as Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT), Wigner–Ville Distribution (WVD), and Discrete Wavelet Transform (DWT) was applied to vibration data of normal rotor and shaft-cracked rotor in speed-varying process and the results of feature extraction from shaft-cracked condition were also compared with those in normal condition.