Damage of carbon fiber reinforced resin matrix composite subjected to laser and tangential gas flow loading

The irradiation effects of 976 nm continuous wave laser on carbon fiber reinforced E-51 resin matrix composite were studied experimentally, with a 0.4 Mach(1 Mach=340 m/s) tangential airflow, a 0.4 Mach tangential nitrogen flow and no gas flow on the target surface, respectively. The ablation laws of the materials were obtained for various laser power densities. Experimental results show that, when the pyrolysis happens severely, the solid particles flowing out of the interface with the pyrolysis gas, will shield the incident laser. The tangential gas flow, on one hand, can weaken the shield effect of the solid particles outflow the interface, which is helpful to the ablation in the irradiated area. On the other hand, the tangential gas flow can cool the target, which is adverse to the ablation. Comparing with the nitrogen gas flow, airflow is of advantage to the combustion of the production, which can heat the downstream area obviously. The loading of the tangential airflow will promote the diffusion of the oxygen to the target surface, which results in the oxidative ablation of the carbon fiber at a low temperature. Under three different gas flow statuses, the utilization ratio of the laser beam decreases with the increasing incident power density, for the power density in the range of 100～800 W/cm².