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In Situ Measurements of Temperature Distribution in a Carbon Fibre Epoxy Composite Irradiated by a Continuous Wave (CW) Chemical Oxygen-Iodine Laser (COIL)
L-C. Long, J-F. Zhang, K. Zhu and Z-W. Ban

This paper studies the temperature field of carbon fibre epoxy composite irradiated by continuous wave (CW) chemical oxygen-iodine laser (COIL) at 1315 nm wavelength. With an infrared thermography technique, the temperature distributions of the back surface of composite sheet with different thickness and under different power density were obtained. The experimental results indicate that with increasing irradiation time, the back surface of the irradiation zone temperature raises rapidly and the time for temperature of centre point of 1.5, 2.1 and 3 mm thick composite sheet to reach 105ºC was 0.98, 1.46 and 2.5 seconds, respectively. The temperature of the back surface continues to rise when irradiation process stopped and the temperature increasing rate gradually decreases until it approaches maximum value. With increasing composite sheet thickness, there is obvious fluctuation in the temperature curves in initial laser irradiation period, and the fluctuation duration is positively correlated with composite sheet thickness. To provide information about the damage mechanism of the heat affected zone (HAZ), the ablation surface of composites was also analysed with a digital microscope.

Keywords: Chemical oxygen-iodine laser (COIL), continuous wave (CW), carbon fibre epoxy composite, ablation, infrared (IR) temperature measurement, damage mechanism, finite element analysis (FEA)

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