Temperature effects on fatigue properties of plain-woven composites by an acoustic-optical-thermal multi-information fusion method

To investigate the temperature effect on the fatigue performance of plain-woven composites, a multi-information fusion method for damage identification under high-temperature conditions was established by integrating acoustic emission (AE), digital image correlation (DIC), infrared thermography (IRT) and scanning electron microscopy (SEM). Equipment for high-temperature AE and DIC acquisition was developed, and fatigue experiments were conducted at room temperature (25 °C), 100 °C, and 150 °C with in-situ observation. The AE data were classified into three clusters using the k-means++ method, corresponding to three damage modes with specific peak frequency ranges: matrix cracking (0 ∼ 200 kHz), fiber/matrix debonding (200 ∼ 400 kHz), and fiber breakage (400 ∼ 700 kHz), respectively. The AE results were cross-validated by analyzing surface temperature and strain fields during the fatigue process. The study revealed that higher temperatures accelerate damage accumulation during fatigue, relieve stress concentration and alter the damage proportion, but have little effect on the influence of fatigue stress levels.