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带太阳帆板航天器刚柔耦合动力学研究 总被引:7,自引:1,他引:6
以带有太阳帆板的航天器为研究对象,计及太阳帆板变形位移场的非线性耦合项,采用假设模态离散变形,基于Kane方程建立起系统的刚柔耦合一次近似动力学模型。分别就大范围刚体运动已知和未知两种情况下进行了数值仿真。仿真结果说明,此模型能准确的预示大范围运动下挠性航天器的动力学行为,而传统的零次近似动力学模型由于丢失了动力刚度项而会得到错误结论。 相似文献
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For efficiently estimating the Profust failure probability based on probability input variables and fuzzy-state assumption, a General Performance Function(GPF) expression is established under the strict mathematical derivation for the Profust reliability model. By constructing the GPF,the calculation of the Profust failure probability can be transformed into the calculation of the traditional failure probability. Then various existing methods for the traditional failure probability can be used to estimate the Profust failure probability. Due to the high efficiency of the Adaptive Kriging(AK) model and the universality of the Monte Carlo Simulation(MCS), AK inserted MCS(abbreviated as AK-MCS) has been proven to be an efficient method for estimating the failure probability. Therefore, the AK-MCS combined with the GPF(abbreviated as AK-MCS + GPF)is proposed for estimating Profust failure probability. The proposed method greatly reduces the computational cost while ensuring the accuracy. Finally, four examples are given to validate the proposed AK-MCS + GPF. The results of the examples show the rationality and the efficiency of the proposed AK-MCS + GPF. 相似文献
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阐述了“先进制造技术与管理”课题的研究背景、研究内容、研究目标及保障措施。拟定的主要研究内容有CAD技术、先进测量技术、先进制造管理技术、新产品开发技术、先进制造经济学。 相似文献
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航天器挠性附件刚柔耦合动力学建模与仿真 总被引:1,自引:0,他引:1
大型挠性航天器在进行轨道机动或姿态调整等大范围刚体运动时,将与其挠性附件的变形运动发生强烈的耦合,传统的零次近似动力学模型已不能正确揭示此时系统的动力学行为。现针对带梁式挠性附件的航天器,在计及挠性附件变形位移场耦合作用的基础上,通过Lagrange方程建立了航天器的刚柔耦合一次近似动力学模型,并利用Wilson-θ方法进行了数值仿真。仿真结果说明,在航天器经历大范围刚体运动时,该动力学模型能够正确预示挠性附件的动力学行为;挠性附件的振动频率随着大范围刚体运动速度的增加而增大,出现了动力刚化现象。 相似文献
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侯国文 《郑州航空工业管理学院学报(管理科学版)》2008,26(5):131-134
电子商务的发展改变了传统会计的运作环境,传统会计的会计假设、会计要素、会计报表和会计实务等方面都面临严峻的挑战。电子商务的出现,使会计假设的基本理论变得模糊,需要进一步的思考;电子商务环境下应把人力资源作为一个重要的会计要素来考虑,同时,应扩大无形资产的核算范围;电子商务环境下网上实时报告会计信息成为可能;会计实务的许多方面已不能适应新的电子环境,需要进行思考和创新。 相似文献
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空-空机炮模态的综合火力/飞行控制系统设计 总被引:2,自引:0,他引:2
针对国产某型号高速歼击机的数学模型及其数字式三轴电传操纵控制增稳系统,采用经典控制理论的方法,在数字式三轴电传操纵控制增稳系统的基础上,分析、设计了一种复杂的非线性控制系统──空-空机炮模态的综合火力/飞行控制系统.文中给出了该控制系统的构成,讨论了火力/飞行耦合器的结构.数学仿真表明,所设计的综合火力/飞行控制系统具有良好的性能,由于采用的飞机数学模型及其数字式三轴电传操纵控制增稳系统的真实性,使得所设计的综合火力/飞行控制系统具有较强的实际意义和工程使用价值. 相似文献
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《中国航空学报》2023,36(4):400-408
When the existing information does not contain all categories, the Generalized Evidence Theory (GET) can deal with information fusion. However, the question of how to determine the number of categories through GET is still intriguing. To address this question, a modified k-means clustering, named centers initialized clustering is proposed, filling the gap of identification and complement of the frame of discernment. Based on this clustering method, the number of categories is determined. The initialized centers selected by center density keep the cluster results constant, enhancing the stability of clustering results. Besides, constructing Generalized basic Probability Assignment (GBPA) modules in a conservative way improves the reliability of the results. The mass of empty set in combined GBPAs is the indicator of the number of categories. Experiments on real and artificial data sets are conducted to show the effectiveness. 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(6):2770-2780
A modified derivation of the criterion of nighttime ozone chemical equilibrium (NOCE) in the mesopause region is presented. According to 3D model calculations, the improved criterion reproduces the lower boundary of the equilibrium much better than its earlier version. Processing of the SABER/TIMED data of 2021 has shown that the modified criterion elevates the NOCE boundary by ~ 0.1–1.7 km, depending on latitude and season. The proposed method of determining the condition of chemical equilibrium can be used to analyse the equilibrium of many trace gases in the stratosphere and troposphere important for different practical applications. 相似文献