Thermoplastic self-reinforced polyethylene (PE/PE) composites were tested under quasi-static tensile load and the failure processes weremonitored by Acoustic Emission (AE) technique. The AE signals were collected and clustered by Unsupervised Pattern Recognition (UPR) scheme. The initiation and progression of the damage mechanisms in the composites can then be reviewed by the cumulative AE hits of each cluster versus strain curves. But the labeling of each cluster is crucial to the failure analysis. The paper focuses on this correlating between the obtained clusters and their specific damage modes. This was carried out by waveform visualization and Fast Fourier Transform analysis. Pure resin and fiber bundles were tested to assist in the labeling of signal classes in the composites (90°, 0° and [±45°] specimens). Typical waveforms of matrix cracking, fiber-matrix debonding, fiber fracture and fiber pullout were indentified respectively. The evolution process of various damage mechanisms in the composites revealed that the correlating method was effective. An objective and repeatable analytical procedure is established for the investigation of progressive failure mechanisms in the thermoplastic composites.
Progressive failure analysis of laminated composite structures
