Recognising Fatigue Damaging Features in Variable Amplitude Loadings Using the S-Transform Approach
This study describes the use of the S-Transform to identify fatigue features in variable amplitude loadings. In normal situation, experimental fatigue loadings exhibit variable amplitude and nonstationary loading pattern, for which the traditional frequency domain analysis cannot provide accurate results. However, the time-localisation transform provides a promising solution. Since the S-transform if the simplification of the advanced time-frequency localization method, i.e., the wavelet transform, it is a good idea to study this transform in order to identify these fatigue features. The results obtained from this study showed that the high amplitude events were detected in the variable amplitude loading based on the difference pattern of the time-frequency localisation. These results were also compared to the plot of moving-damage using the Morrow’s strain-life fatigue damage model. Based on the promising outcomes, finally, it is proposed that further study of the S-transform should be carried out in broader scope of fatigue life assessment.