中国液体运载火箭结构系统发展规划研究

结构系统是运载火箭关键系统之一,对运载效率提升具有显著作用。深入研究了国外运载火箭结构系统发展现状,根据我国运载火箭发展需求,结合我国航天发展和基础工业实际情况,从材料、结构形式、制造工艺等方面,提出了我国运载火箭结构系统重点发展方向和主要关键技术,对提升运载效率和推动航天强国建设具有重要的工程意义。     

Stochastic structural optimization using particle swarm optimization, surrogate models and Bayesian statistics

This paper focuses on a method to solve structural optimization problems using particle swarm optimization (PSO), surrogate models and Bayesian statistics. PSO is a random/stochastic search algorithm designed to find the global optimum. However, PSO needs many evaluations compared to gradient-based optimization. This means PSO increases the analysis costs of structural optimization. One of the methods to reduce computing costs in stochastic optimization is to use approximation techniques. In this work, surrogate models are used, including the response surface method (RSM) and Kriging. When surrogate models are used, there are some errors between exact values and approximated values. These errors decrease the reliability of the optimum values and discard the realistic approximation of using surrogate models. In this paper, Bayesian statistics is used to obtain more reliable results. To verify and confirm the efficiency of the proposed method using surrogate models and Bayesian statistics for stochastic structural optimization, two numerical examples are optimized, and the optimization of a hub sleeve is demonstrated as a practical problem.     

维修执行方案的制订与优化

维修方案作为飞机持续适航的基础文件,在确保安全、适航的前提下,航空公司应根据自身航班运行特点,结合自身维修资源（设备设施、人力和材料等）的具体情况,科学、合理地制订维修执行方案并不断持续优化,从而达到最大化使用维修资源,降低维修成本,减少飞机检修停场,提高飞机的可用率及整体经济效益。本文主要以南航空客机队（A330／A380）维修执行方案为例,探讨如何制定与优化维修执行方案。     

基于双代号时标网络计划的航线保障翌序分析研究

双代号时标网络技术是一种在建筑工程领域运用比较成熟的技术．本文首次将该技术运用于航线保障程序中,从中找出关键线路并计算保障工期,最后依据保障工期和关键线路．对航线保障程序进行分析．从而为合理安排航班提供依据．并在一定程度上缓解因航线繁忙导致的航班延误。     

着陆姿态不确定下的着陆器缓冲机构优化设计

以某型着陆器为研究对象，建立其软着陆过程的动力学仿真模型，并结合Monte Carlo法研究不确定着陆姿态下的某型软着陆性能。然后，分析着陆器的软着陆性能与其缓冲机构构型参数之间的相关关系，并基于实验设计方法与动力学仿真模型得到样本点，建立以着陆器缓冲机构构型参数和着陆姿态参数为输入、软着陆性能指标值为输出的响应面模型。最后，基于响应面模型，考虑着陆器姿态的不确定性，运用结合第二代非劣排序遗传算法(NSGA-II)和多岛遗传算法(MIGA)的分级优化方法实现了着陆器缓冲机构的优化计算，得到了最佳缓冲机构构型参数。通过仿真模型校验，优化后着陆器的抗翻倒能力与底面抗损坏能力分别提升了3.546%和 5.140% 。     

High cycle fatigue failure with radial cracks in gears of aero-engines

The gears in aero-engines perform energy and motion transfer between the High-Pressure Rotor (HPR) and accessories. Firstly, an occurred fault with radial cracks in the driven gear disk was diagnosed as High Cycle Fatigue (HCF) failure through necessary examinations. Analysis of fault tree and test signals indicated that the fracture was relevant to the swing vibration of the driven gear excited by the unbalance excitation on HPR. Secondly, a corresponding mechanism model was established, in which the gear meshing effect was considered, with lateral and swing vibration mode. The Governing Equations (GEs) and the Finite Element Model (FEM) were established and verified. Then, the modal shapes, harmonic response, and transient response were analyzed, indicating that the swing vibration of the driven gear could be significantly excited by the unbalance on HPR, which induced the cracks in the driven gear disk to extend radially. Furthermore, influences of factors on the unbalance response were obtained, in which the unbalance response appeared local minimum points and maximum points. Meanwhile, 1# and 2# bearing stiffness had rather significant influences on the response. Thus it is efficient to modify them to achieve vibration control.     

基于SFA的研制阶段装备保障方案评价模型

针对目前研制阶段装备保障方案评价在角度和方法上的不足,提出基于随机前沿分析(SFA)的评价模型。首先,分析提炼保障系统的特性,在此基础上,建立保障系统的特性评价参数,然后构建基于SFA的评价模型,通过计算保障方案的效率指数进行保障方案的评价,实现了保障方案的排序,以及评价指标的灵敏度分析。最后,结合研制阶段某型号飞机保障方案给出评价示例,并与数据包络分析(DEA)评价结果进行对比分析,评价结果具有较高的一致性,从而验证了该模型的可行性和有效性,可为研制方在研制阶段保障方案的评价决策和改进设计提供有效的技术支持。     

固定翼反潜机浮标阵监听飞行航路规划研究

本文结合工程实际应用,研究了固定翼反潜机对浮标阵监听飞行航路规划问题。分析了浮标阵存在公共监听区域的条件,对于不能整体监听覆盖的浮标阵,提出了监听航路的评价指标。针对固定翼反潜机执行监听任务时,属于近距离航路规划范畴,飞行航路受载机机动转弯性能约束的影响较为显著,对监听航路采用了一定转弯策略,并用遗传算法搜索生成监听航路,取得了较好的效果。     

航空发动机双转子系统的随机激励响应分析

针对航空发动机双转子系统受到一些无法预测的激励产生随机振动的现象,建立了不平衡双转子系统在随机激励作用下的运动方程。运用虚拟激励法,计算双转子系统在随机力下的位移响应功率谱密度,对其结构动力特性进行了研究。研究表明,当中介轴承刚度系数增大时,系统的固有频率增大并趋于定值。此时,外随机力引起的位移响应谱密度峰值减小并趋于无穷小值,而系统耦合作用引起的位移响应谱密度峰值先上升后减小,并在某个刚度值后,趋于无穷小值。根据研究结果提出了一些预防航空发动机双转子随机振动危害的措施。     

民用飞机飞行模拟机数据包试飞任务优化结合方法研究

飞行模拟机数据包试飞用于获取飞行模拟机研制及鉴定所需的试飞数据,涉及多项试飞科目。为提高试飞效率、降低试飞成本,针对飞行模拟机数据包试飞与型号试飞的优化结合方法进行了研究。通过分析飞行模拟机研制进度要求、型号试飞规划、型号构型到位计划,以及飞行模拟机数据包试飞和型号试飞各试飞科目的试飞要求等要素,分别在试飞科目分析阶段和试验点分析阶段提出了不同的优化结合原则,包括试飞方法相似原则、科目类别相似原则、前置试验满足原则及构型要求兼顾原则。并给出了直接结合、试验点连续结合、形态变换结合及架次结合四种优化结合方法,以及优化结合方法所适用的飞行模拟机数据包试飞阶段。该优化结合方法已在实际型号飞行模拟机数据包试飞任务规划中得到应用,起到了减少试飞任务量的作用。