离轨薄膜帆原子氧侵蚀的缺陷密度效应数值模拟研究  

Numerical Simulation on Atomic Oxygen Undercutting of Deorbit Sail Using Monte Carlo Method

作　　者：傅宇蕾 恽卫东 曹争利 彭福军 耿海峰 孙承月[2] 吴宜勇[2] FU Yu-lei;YUN Wei-dong;CAO Zheng-li;PENG Fu-jun;GENG Hai-feng;SUN Cheng-yue;WU Yi-yong(Shanghai Key Laboratory of Spacecraft Mechanism,Aerospace System Engineering Shanghai,Shanghai 201108,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]上海宇航系统工程研究所上海市空间飞行器机构重点实验室,上海201108 [2]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《空间碎片研究》2020年第2期14-21,共8页Space Debris Research

摘　　要：离轨薄膜帆在离轨过程中要长期暴露在低地轨道较为恶劣的空间环境中,其中原子氧对帆面薄膜材料的侵蚀效应会导致帆面结构损伤严重。为了合理评估离轨薄膜帆帆面材料的寿命,本文基于对帆面孔隙、裂纹、折痕等缺陷的试验表征结果,采用蒙特卡洛数值模拟方法,建立数值仿真模型,分析不同尺度缺陷下原子氧对帆面材料的侵蚀情况,重点研究了帆面薄膜材料的原子氧掏蚀缺陷密度效应。以离轨帆从750km轨道经历38个月的离轨过程为例进行研究,计算结果表明:帆面宽度缺陷为500nm和1μm时,原子氧侵蚀作用下掏蚀形貌深度分别为1.2μm和1.4μm,掏蚀宽度分别为600nm和1.1μm。通过将仿真结果与NASA的长期暴露试验结果进行比对,验证了模型的有效性。该模型可为离轨帆寿命评估提供初步的理论依据。Deorbit sails are used in the low Earth orbit(LEO)to reduce the growing orbital debris by rapidly removing satellites from orbit after the end of operational missions.In LEO,atomic oxygen(AO)is a potential threat to the long duration exposure facilities.The sail itself consists of mylar membrane.The aluminized coatings have been used on the deorbit sail to protect the underlying polymers.However,the process of folding and unfolding for the sail will induce some defects on the membrane inevitably,which will act as the optimal sites for the onset of the AO attack.In this paper,the defects on the drag sails are experimentally measured.The Monte Carlo model is developed.The crease width ranges from 500 nm to 1μm according to the observation of scanning electron microscope(SEM).As the defects’density and gap-size are comparable to the thickness of membrane,the interaction effect of atomic oxygen undercutting between the adjacent defects is studied.The maximal undercutting depth for the deorbit drag sail within the predicted 37 months’deorbit time is 1.2μm and 1.4μm for the defect width of 500 nm and 1μm.The undercutting width for the deorbit sail with width of 500 nm and 1μm is predicted to be 600 nm and 1.1μm.The computational predictions of the AO undercutting at defect sites are validated by the NASA long duration exposure facility experimental data.The simulated results provide the design references for the engineering applications of the deorbit sail.

关 键 词：离轨帆 原子氧掏蚀 蒙特卡洛方法 缺陷密度效应 

分 类 号：V417+.6[航空宇航科学与技术—航空宇航推进理论与工程]