Evaluation of Failure Modes of Pure Resin and Single Layer of Adhesively Bonded Lap Joints Using Acoustic Emission Data

Abstract

The purpose of this present study is to monitor the failure modes of pure resin and single layer of adhesively bonded lap joints using acoustic emission (AE) technique under tensile loading. Parametric analysis is performed using AE count rate, cumulative counts, time, frequency, amplitude and duration on the AE data obtained during the tensile test of adhesively bonded lap joints. After preliminary investigations in the parametric analysis, it was seen that AE amplitude parameter changes with the different AE events, thus failure modes were characterized using frequency analysis. Fast fourier transform (FFT) analysis has been proposed to identify the importance of peak frequency content of each failure mode corresponding to the AE hits using frequency FFT analysis. Short time fast fourier transform resulting frequency is correlated with FFT analysis of AE data, to find the peak frequency ranges for each of the failure modes. Scanning electron microscope as complementary, post-test inspection method is used to find microscopic evidence for the assumed assignment of failure modes.