Time-Frequency Localisation Analysis for Extracting Fatigue Damaging Events

The fatigue feature extraction using the Short-Time Fourier Transform (STFT) and wavelet transform approaches is presented in this paper. The transformation of the time domain signal into time-frequency domain computationally implemented using the STFT and Morlet wavelet methods provided the signal energy distribution display with respect to the particular time and frequency information. In this study, cycles with lower energy content were eliminated, and this selection was based on the signal energy distribution in the time representation. The simulation results showed that the Morlet wavelet was found to be a better approach for fatigue feature extraction. The wavelet - based analysis obtained a 59 second edited signal with the retention of at least 94 % of the original fatigue damage. The signal was 65 seconds (52 %) shorter than length of the edited signal that was found using the STFT approach. Hence, this fatigue data summarizing computational algorithm can be used for accelerating the simulation works related to fatigue durability testing.