离子推力器栅极力学性能模拟分析研究

Simulation of Dynamical Properties in Launch Environment of Carbon Fiber Composite Grid of LIPS-100 Ion Thruster Optics

为了对LIPS-100离子推力器栅极优化设计提出合理建议,利用结构动力学计算模型开展栅极力学特性分析,研究8.6 grms随机振动和800 g加速度冲击力学环境对栅极的影响。采用ABAQUS有限元软件模拟分析了两种不同弹性模量的碳纤维复合材料层合结构栅极力学性能,并和传统金属钼栅作对比,研究发现:碳栅和钼栅都满足技术要求中首阶共振频率大于100 Hz的要求,且最大应力均满足输入载荷条件,不存在破坏性应力,其中碳栅应力安全系数要高于传统金属钼栅。栅极形变量应是设计过程中考虑的首要因素,冲击造成的形变要大于随机振动,提升弹性模量31.16%可使碳栅冲击形变减小13.17%。采用模量较高的碳纤维制备碳栅可使栅间距由现有的0.80降低至0.69 mm,从而可使最大推力提升10.72%。

The dynamical behavior of the carbon-fiber composites grid,of LIPS-100 ion thruster optics in the launch environment（ 8. 6grms random vibration and 800 g shock-load）,was mathematically modeled,theoretically analyzed and numerically simulated in finite element method with software ABAQUS for the purpose of design optimization. The impact of the elastic modulus of the two laminated carbon-fiber grids and one Mo-grid on the stress distribution and deformation was investigated. The simulated results show that the carbon-fiber composite grids outperform Mo-grid because of higher safety-factor,narrower grid-gap and 10. 72% stronger maximum-thrust; and that the grid deformation depends strongly on the shock-load but weakly on the random vibration. A 31. 16% increase in the elastic modulus of carbon-fiber grid decreases the shock-load induced deformation by 13. 17%. The influence of the electrostatic attraction on the grid deformation remains to be studied.