Fatigue crack localisation based on empirical mode decomposition and pre-selected entropy

ABSTRACTFatigue cracks, especially at their initial stage, can lead to a repetitive crack open-close breathing-like phenomenon in the vibration response of structural elements. As such, regularities, bi-linearity, or perturbations in the vibration response can arise. Entropy can be used to quantify the irregularity or bi-linearity in these responses since there is an apparent variation of entropy values on the two sides of a breathing crack. Here, we present a new breathing crack localisation method based on a spatially distributed entropy approach coupled with the empirical mode decomposition technique. To enhance the robustness, a pre-selection mechanism is proposed to select the most suitable entropy method. The proposed method is then employed to localise the breathing crack in a beam in a laboratory setup. It is concluded that the proposed approach can be effectively used for breathing crack localisation in a structural element.KEYWORDS: Crack localisationstructural health monitoringentropyempirical mode decompositionbreathing phenomenon Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThe first author is funded by the China Scholarship Council (CSC) from the Ministry of Education of P.R. China. This research was undertaken, in part, thanks to funding support from the Natural Sciences and Engineering Research Council of Canada (NSERC).