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初值不确定轨道可达区域计算 被引量:9
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作者 石昊 赵育善 +2 位作者 师鹏 温昶煊 郑翰清 《宇航学报》 EI CAS CSCD 北大核心 2016年第4期411-419,共9页
为计算航天器轨道初值不确定造成的可达区域(RD),提出一种适用于椭圆参考轨道的计算方法。以航天器的名义轨道作为基线,定义一个随时间变化的移动参考平面,在此移动平面上建立名义轨道到可达区域上任一点的距离函数,函数的极大值点即为... 为计算航天器轨道初值不确定造成的可达区域(RD),提出一种适用于椭圆参考轨道的计算方法。以航天器的名义轨道作为基线,定义一个随时间变化的移动参考平面,在此移动平面上建立名义轨道到可达区域上任一点的距离函数,函数的极大值点即为可达区包络的边界点,从而将问题转换为非线性方程组的求解问题,并对动力学模型部分线性化带来的误差进行了分析。随后采用变参数的自适应同伦算法对方程组进行求解。最后对航天器释放微小卫星的实例进行数值仿真,结果显示该方法可行有效。 展开更多
关键词 轨道不确定性 相对可达区 参考平面 线性化
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Probabilistic model and analysis of coupled train-ballasted track-subgrade system with uncertain structural parameters 被引量:5
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作者 MAO Jian-feng XIAO Yuan-jie +2 位作者 YU Zhi-wu Erol TUTUMLUER ZHU Zhi-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第7期2238-2256,共19页
Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduce... Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system. 展开更多
关键词 coupled train-ballast-subgrade system structural parameter uncertainty stochastic dynamic analysis probability density evolution method wheel-rail interaction
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