Laser Irradiation Behavior of Carbon Fiber Epoxy Resin Composites with Laminar Structure

Laser attracts more attention and it could cause material failure by its high energy. Carbon fiber resin composites are widely used in aerospace vehicles experiencing dramatic damage to their surface if exposed to high-energy laser irradiation. The available studies on irradiation behavior are mainly focused on pulsed lasers and bulk composites, and investigations of thin laminar structures under continuous-wave laser irradiation have rarely been reported. In this study, the damage behavior of laminar carbon fiber epoxy resin composites (CFE composites) was studied. Using a threshold model of resin pyrolysis, CFE composite is observed to be damaged at 0.18 s when irradiated at 100 W/cm2, and if the laser power density is increased to 200 W/cm2 for 2 s, no resin remains on the fiber surface, which is now completely exposed. With an increase in power density and irradiation time, the ablation rate always shows an upward trend: the ablation region expands and the separation of layers in the interior appears, which can reach 0.01156 g/s when irradiated at 100 W/cm2 for 5 s. The damage mechanism of CFE composite was also revealed by the temperature evolution data, thermogravimetric analysis, and composition change.