实验研究了样品表面有切向空气气流、切向氮气气流和无气流时, 976 nm连续激光对玻璃纤维增强E-51环氧树脂复合材料的辐照效应。结果表明:无气流时, 喷出的热分解产物会对入射激光产生屏蔽作用; 有气流时, 激光对玻璃纤维的破坏方式是其升温熔化后再被切向气流带走; 当激光功率密度较低时, 切向空气气流以加强样品表面的对流冷却作用为主, 不利于激光对玻璃纤维复合材料的破坏; 当激光功率密度较高时, 切向空气气流以降低屏蔽作用和提供氧气助燃为主, 有利于激光对玻璃纤维复合材料的破坏。三种气流状态下, 质量损失随功率密度呈现单调增加趋势, 当入射激光功率密度在100~600 W/cm2范围内, 随着功率密度的增大, 激光能量的利用效率逐渐增大并趋于稳定。

The irradiation effects of 976 nm continuous wave laser on glass fiber reinforced E-51 resin matrix composite are studied experimentally, with a 0.4Ma tangential airflow, a 0.4Ma tangential nitrogen flow and no gas flow on the target surface, respectively. Experimental results show that, the incoming laser beam will be severely affected by the gaseous pyrolysis products while without gas flow on the target surface, and the loading of tangential gas flow will reduce the influence. The failure mode of glass fiber is that it melts and then is blown away by gas flow, when laser irradiation happens in the presence of a gas flow parallel to the specimen surface. The main function of the tangential airflow is to enhance the convection cooling effect for a low laser irradiance, thus the tangential airflow is not conductive to the laser damage of glass fiber composite. When the laser irradiance increases, the main functions of the airflow are to reduce the shielding effect of the gaseous pyrolysis products on the incoming laser beam and to supply oxygen, thus the loading of the tangential airflow is advantageous to the laser damage of glass fiber composite. Under three different gas flow states, the mass loss increases with the increasing incident power density. The utilization ratio of laser beam increases up to a saturation value as the incident power density is in the range of 100-600 W/cm2.