ON THE NEED TO CORRELATE ACOUSTIC EMISSION AND FATIGUE STRAIN SIGNALS ASSOCIATED TO METALLIC COMPONE

This study discusses the relationship between signals collected from two different sensors, i.e. strain gauges and acoustic emission (AE) piezoelectric transducer in order to assess fatigue failure of metallic components. Both sensors were attached to the SAE 1045 steel specimen during fatigue cyclic test at constant load condition. Three different loads were applied to a specimen during the test in order to observe the different behaviour of the signals. The measured strain loadings were analysed in order to obtain the predicted fatigue life values experienced by the specimens using the three strain-life fatigue models; Coffin-Manson, Morrow and Smith-Watson-Topper. The experimental fatigue lives were based on the number of cycles to failure from the servo-hydraulic fatigue testing machine during the test. In addition, the obtained AE signals were analysed using the global statistical values of the root mean square (r.m.s) and the kurtosis. Thus, a correlation between experiment and predicted value of fatigue life was established. Apart of that, a good correlation between the AE parameters (r.m.s and kurtosis) and the value of predicted fatigue life was also established to confirm that AE technique can be one of tool to predict structural life besides other methods