Development of a method for estimating the time-of-arrival of acoustic emission signals for structural health monitoring

Purpose This study aims to develop a novel method for estimating the time-of-arrival (ToA) of acoustic emission (AE) signals generated by materials under loading. To use the estimated ToA to analyse damage evolution in the material. Design/methodology/approach The ToA estimation method is developed based on the Akaike information criterion (AIC) with an addition of entropy in the maximum likelihood estimation. Carbon fibre reinforced polymer (CFRP) specimens in short beam shear (SBS) configuration are tested to generate the AE signal required for the study. The specimen is subjected to a three-point bending load and its damage evolution is analysed by the estimated ToA, peak amplitude and peak frequency of the AE signals. Findings The proposed ToA estimation method works efficiently even for AE signals with a large number of reverberations. The damage evolution in the SBS specimen is mainly due to matrix cracking, delamination in the inner plies and interlaminar crack growth. AE signals with different levels of peak amplitude, peak frequency and varying ToAs are able to identify these different damage sources. Originality/value The proposed ToA estimation method performs better than the traditional methods based on AIC. Its application can be extended to AE signals generated from large structures.