Near-infrared Laser-induced Thermal Damage on Carbon Fiber Reinforced Plastics

Abstract

Thermal damages to carbon fiber reinforced plastics (CFRP) subjected to continuous wave near-infrared (CW NIR) laser irradiation are investigated. CFRP specimens are illuminated with a 1070 nm wavelength CW NIR laser. While the laser beam irradiates the samples, an infrared thermometer measures the surface temperature and a charge-coupled device camera collects images. After laser irradiation, the surface morphology of each specimen is examined. The experimental results show that an ignition phenomenon occurs on the CFRP surface first. Then, with increasing irradiance or irradiation time, swelling phenomenon and penetration ensue. From the experiments, ignition and penetration times are measured according to the laser power. A convection effect during swelling and penetration is also discussed. A numerical model for ignition is developed based on heat transfer analysis; the simulation results are in good agreement with the experimental findings.