月球探测器着陆腿动力学建模与仿真
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摘要
在月球探测器多工况着陆仿真分析中,要求所建模型能够满足高效运算的需求。本文改进简化着陆腿有限元建模:分别采用壳单元、梁单元模拟着陆腿内外筒壁,充分考虑结构柔性以及筒壁间作用力;通过连接单元特性来表达缓冲材料的力学性能,减少了计算耗时;并采用隐式算法求解动力学方程,保证了计算精度。其中壳单元模型能够更全面地反映缓冲腿柔性变形对缓冲性能的影响;在考虑着陆腿柔性时,随着摩擦因数的增大,着陆腿缓冲性能随之下降。
A simplified model is presented for cushion legs.Shell elements and beam elements are separately used to simulate the cylinders,taking the flexibility and the friction force of landing legs into consideration.Connector elements are used to present the dynamic performance of crushable material,improving the computational efficiency.Implicit dynamics procedure is introduced to ensure the calculation accuracy.The results show that shell element model can reflect the effect of legs′flexibility on landing performance better,meanwhile,as friction coefficient increasing,the energy absorption capabilities of legs are decreased.
A simplified model is presented for cushion legs.Shell elements and beam elements are separately used to simulate the cylinders,taking the flexibility and the friction force of landing legs into consideration.Connector elements are used to present the dynamic performance of crushable material,improving the computational efficiency.Implicit dynamics procedure is introduced to ensure the calculation accuracy.The results show that shell element model can reflect the effect of legs′flexibility on landing performance better,meanwhile,as friction coefficient increasing,the energy absorption capabilities of legs are decreased.
引文
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[4]万峻麟,聂宏,陈金宝,等.月球着陆器有效载荷着陆冲击响应分析[J].宇航学报,2010,31(11):2456-2463.Wan Junlin,Nie Hong,Chen Jinbao,et al.Impact response analysis of payloads of lunar lander for lunar landing[J].Journal of Astronautics,2010,31(11):2456-2463.
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[6]Doiron H H,Zupp G A.A mathematical procedure for predicting the touchdown dynamics of a soft-landing vehicle[R].Houston:Manned Spacecraft Center,NASA TN D-7045,1971.
[7]梁东平,柴洪友.着陆冲击仿真月壤本构模型及有限元建模[J].航天器工程,2012,21(1):18-24.Liang Dongping,Chai Hongyou.Lunar soil constitutive and finite element modeling for landing impact simulation[J].Spacecraft Engineering,2012,21(1):18-24.