Theoretical study of flow ripple for an aviation axial-piston pump with damping holes in the valve plate

Based on the structure of a certain type of aviation axial-piston pump＇s valve plate which adopts a pre-pressurization fluid path （consisting a damping hole, a buffer chamber, and an orifice） to reduce flow ripple, a single-piston model of the aviation axial-piston pump is presented. This sin- gle-piston model comprehensively considers fluid compressibility, orifice restriction effect, fluid resistance in the capillary tube, and the leakage flow. Besides, the instantaneous discharge areas used in the single-piston model have been calculated in detail. Based on the single-piston model, a multi-piston pump model has been established according to the simple hydraulic circuit. The sin- gle- and multi-piston pump models have been realized by the S-function in Matlab/Simulink. The developed multi-piston pump model has been validated by being compared with the numerical result by computational fluid dynamic （CFD）. The effects of the pre-pressurization fluid path on the flow ripple and the instantaneous pressure in the piston chamber have been studied and opti- mized design recommendations for the aviation axial-piston pump have been given out.     

石英纤维增强天线罩烧蚀应力耦合试验及仿真分析

介绍了新的一种针对纤维增强复合材料天线罩的边烧蚀边加载的热力耦合试验方法,该试验方
法通过燃气流发动机及应力载荷加载装置实现了天线罩烧蚀状态下的应力考核,针对此试验方法开展了仿真
模拟计算,通过仿真数据与试验测试数据对比验证了烧蚀应力耦合仿真计算方法的正确性,从试验和理论分析
两个角度反映了纤维增强结构天线罩在烧蚀状态下的强度,为天线罩烧蚀应力耦合试验与纤维增强复合材料
的仿真计算开辟了一条新途径。     

滚弯成形解析建模与数值分析

建立了考虑材料塑性强化的滚弯成形力学分析解析模型,推导出了应力应变、残余应力以及回弹半径计算公式.基于非线性有限元软件,对滚弯成形进行了动态模拟,对应力应变状态、塑性应变分布、残余应力以及回弹等进行了分析计算,结果表明:板料滚弯成形初始效应明显,下压点附近曲率不均匀;采用足够的滚弯时间后,中间段的曲率均匀度很好;成形半径与上辊下压量呈近似幂函数关系;多道次滚弯可以减小两端的曲率波动和最大应力应变.最后通过与滚弯成形试验数据的对比,分析和验证了解析模型与数值模型的适用性和精度.     

无人机前开伞式降落过程动力学建模与仿真

文章分析了某型无人机降落伞回收阶段的动力学过程,对各工作阶段的无人机和降落伞的组合体进行了数学建模,使用Matlab软件中的Simulink组件搭建了无人机伞降过程的仿真模型,按照真实飞行和回收工况进行了计算,通过仿真结果与试验数据的比较,验证了模型的正确性.     

XZG—2型综合告警器的研制

ＸＺＧ－２型综合告警器是配装在ＪＬ８飞机上的机载成件。本文介绍了该告警器的结构特点、工作原理及研制情况。     

基于SysML的远程专家保障装备体系建模及结构评估

未来联合作战呈现出体系对抗体系的特点,为满足作战需求对武器装备体系设计提出了更高的要求,实现动态作战环境下武器装备体系结构建模和评估是体系设计中的重要内容。基于联合作战背景下的远程专家保障装备体系想定,从体系作战需求角度出发通过SysML(系统建模语言)建立体系结构模型,设计远程专家保障装备体系结构视图产品,结合ExtendSim建立了可执行模型,并进行仿真分析和结构评估,为提升体系能力提出有效可行的建议。     

民机典型前缘结构抗鸟撞分析研究

为保障飞行安全,CCAR25 部对民机结构抗鸟撞性能提出了严格的指令性要求,须对机翼前缘、平尾前缘和垂尾前缘等典型前缘结构进行鸟撞分析。鸟撞分析涉及到结构的动力学分析、鸟体的本构关系模拟、材料的高速非线性效应以及结构大变形等多方面因素的影响,相关的计算复杂,会耗费结构设计人员大量的精力和时间。通过采用经验公式和仿真分析方法对前缘结构抗鸟撞性能进行快速的分析,可达到对结构的抗鸟撞能力进行快速预估并从而指导设计的目的。     

Study on ballistic penetration resistance of titanium alloy TC4, Part II: Numerical analysis

Enhancing containment capability and reducing weight are always great concerns in the design of casings. Ballistic tests can help to mitigate a catastrophic event after a blade out, yet taking time and costing money. A wise way is to hunt for a validated numerical simulation technology, through which the material dynamic behavior over the strain rate range in the ballistic tests should be represented and reasonable failure strain should be defined. The simulation results show that the validation of the numerical simulation technology based on the test data can accurately estimate the absorption energy, describe the physical process and failure mode during the penetration, as well as the failure mechanism. It is found that energy dissipation of projectiles is in manner of compression stage, energy conversion stage, and interactive scrap stage. An effect indicator is proposed, where the factors of critical velocity including impact orientation and mass of projectiles and thickness of casings are considered. The critical velocity presents a linear relation with the effect indicator, which implies the critical velocity obtained by the flat casing could underestimate the capability of the real casing.     

一种GEO/LEO双层卫星网络路由算法及仿真研究

时间虚拟化策略的时间片过短将影响路由性能,提出一种基于GEO/LEO双层卫星网络的时间虚拟化和分层管理的路由算法（VLRA）,对时间虚拟化策略进行合理改进,通过新的分层管理思想,在每个时间片开始进行路由计算和更新。分析和仿真验证表明,改进的时间虚拟化策略得到的时间片更合理,利于网络的路由和通信。GEO/LEO双层卫星网络下VLRA算法时延稳定,并具有较好的丢包率和吞吐量性能。     

再循环对飞机空调系统性能影响分析

结合国内民航客机环境控制系统的研制需求,利用热力学理论建立了再循环系统各附件数学模型,并编制了系统仿真程序。通过仿真对再循环系统设计参数与空调系统的稳、动态指标之间的影响因素进行了研究,并得出再循环系统的设计原则和参数选取范围。将其结论应用于某型飞机环境控制系统的研制中,效果良好。