复杂作业模式下车间生产调度的建模与优化

针对某航天制造企业的实际生产环境,分析和讨论了复杂作业模式下车间生产的调度问题,并根据实际的业务流程建立了数学模型,通过自动调度与人工调度相结合的方法对其进行优化,最后采用实例对调度结果进行了验证.事实证明,这种调度机制可以同时增强系统的灵活性和稳定性,对提高车间生产效率和管理水平有很大帮助.     

某型航空发动机锯齿冠涡轮叶片叶冠间隙扩展规律研究

以某型航空发动机锯齿冠涡轮叶片实际外场叶冠间隙监控数据为统计样本,开展了叶片叶冠间隙扩展规律的统计分析与研究,包括叶冠间隙扩展典型规律和扩展速率的统计分析,松动叶片数量与叶冠间隙的对应关系以及叶冠出现间隙的发动机使用情况的统计分析。结果表明:叶冠间隙存在稳态扩展和异常扩展阶段,且松动叶片数量与叶冠总间隙之间存在一定的比例关系,可为叶冠间隙外场监控提供参考和依据。     

当前我国战略性贸易政策工具的选择

以贸易政策的两点基本要求——利用贸易获取利益和促进本国产业升级作为衡量标准，我国现行贸易政策的实施效果并不理想，导致我国对外贸易部门获利能力很弱，同时贸易政策与产业发展政策相脱节。无论从短期还是从长期来看，我国由传统贸易政策向战略性贸易政策转变已经成为必然。然而，我国在战略性贸易政策的实践中必须对不同的战略性政策工具进行选择，选择适合于我国国情的贸易政策工具，并对不同贸易政策工具在我国的具体实施途径进行不同的安排。     

中低空高度下变后掠翼的最佳变后掠规律

为寻找到可变后掠翼飞机的最佳变后掠规律,利用CATIA生成不同后掠角模型,使用Fluent模拟不同高度的环境并利用遗传算法得出最佳的变后掠规律,最后将计算数据进行拟合分析.研究结果表明,在不同高度下,最佳变后掠规律大体趋势相似,但5000m时优势略明显.这个结论为今后可变机翼无人机的设计提供了一定的依据.     

运输类直升机仪表飞行规则下的设备和系统的适航验证方法研究

直升机按照驾驶和领航条件可划分为目视飞行规则和仪表飞行规则。我国现有已取得型号合格证的直升机大都是目视飞行规则,使用受限制较多。综合分析了直升机仪表飞行规则的适航要求,提出验证方法以及在AC313型机的验证结果,对直升机申请仪表飞行规则以及目视飞行规则升级到仪表飞行规则具有一定的指导意义,对新型号研制也具有参考价值。     

Haynes 282新型高温合金晶粒长大行为及数学模型研究

为了研究新型合金在高温状态下的晶粒长大行为,进行了Haynes 282合金在973～1 373 K条件下保温0～10 800 s的晶粒长大实验,通过实验分析了保温时间和保温温度对其晶粒尺寸的影响,研究了晶粒尺寸在其实验条件下的演变规律。由此构建了符合Haynes 282合金晶粒长大的数学模型,该模型的建立能够有效表征Haynes 282合金在高温下的晶粒长大行为。     

航空发动机传动系统技术成熟度评价方法的应用

针对传动系统故障频发的研制现状,提出基于传动系统的技术分解结构(TBS),制定各项技术的成熟度评价专用细则,并根据专用细则制定全面开展评价工作的流程和方法。专用评价细则的建立是传动系统技术成熟度评价工作的核心,实现了对发动机通用细则的解读,且通过对细则满足情况的判定,明确了该项技术的成熟度提升方向。应用实例表明:该项工作对控制传动系统研制过程中的技术风险具有重要意义,也为承研单位制定技术能力提升计划奠定了坚实的基础。     

Reduction rules-based search algorithm for opportunistic replacement strategy of multiple life-limited parts

The opportunistic replacement of multiple Life-Limited Parts(LLPs) is a problem widely existing in industry.The replacement strategy of LLPs has a great impact on the total maintenance cost to a lot of equipment.This article focuses on finding a quick and effective algorithm for this problem.To improve the algorithm efficiency, six reduction rules are suggested from the perspectives of solution feasibility, determination of the replacement of LLPs, determination of the maintenance occasion and solution optimality.Based on these six reduction rules, a search algorithm is proposed.This search algorithm can identify one or several optimal solutions.A numerical experiment shows that these six reduction rules are effective, and the time consumed by the algorithm is less than 38 s if the total life of equipment is shorter than 55000 and the number of LLPs is less than11.A specific case shows that the algorithm can obtain optimal solutions which are much better than the result of the traditional method in 10 s, and it can provide support for determining tobe-replaced LLPs when determining the maintenance workscope of an aircraft engine.Therefore,the algorithm is applicable to engineering applications concerning opportunistic replacement of multiple LLPs in aircraft engines.     

DOS多任务远程通讯系统的设计与实现

本文介绍作者在ＤＯＳ上开发的多任务远程通讯系统，它可以实现微机之间的远程数据传送、命令控制、定时收发等功能。该程序常驻内存，在后台进行数据通讯。在数据传送期间用户仍可执行ＤＯＳ命令或继续执行程序，在ＤＯＳ上实现了多任务的并发。该系统具有与程序员和用户的两套接口，用户通过命令调用其功能，而程序员可在汇编，Ｃ，ＦＯＸＢＡＳＥ等语言源程序中实现后台数据通讯。     

Space debris mitigation measures applied to European launchers

In November 1986, more than 20 years ago, an H8 upper stage of Ariane 1 exploded in orbit nine months after the end of its mission. So as to avoid the generation of debris in low Earth orbit, a dedicated complementary development modified the design, introducing systematic passivation of the stage. Ever since this event, space debris mitigation has been a major concern for all launcher activities in Europe.After a short recall of the launchers currently operated by Arianespace as well as those currently developed by ESA with CNES, particularly for the safeguard authority, including the most promising future evolutions, the set of applicable regulations is described. These rules are fundamentally derived from the IADC Guidelines (hence the UNCOPUOS ones), translated into European Code of Conduct and in some more applicable Standards, such as the one prepared by ESA. The process of preparing ISO standards, mainly through the ECSS Working Group, is also described.Three major families can be identified: minimization of Mission Related Objects, Passivation of stages at the end of mission, and orbital protected zones including the so-called 25-year rule.The paper describes how European launchers do or will fulfill these applicable standards, quantifying the efficiency of the mitigation rules, and describing improvement actions currently under study.