基于多目标优化的液体火箭发动机减损与延寿控制

着重分析了减损与延寿控制律的综合过程,提出其基于多目标优化方法的理论基础。在建立某型液体火箭发动机系统动力学模型、关键部件之涡轮叶片的结构分析模型及其材料损伤模型的基础上,分析了应用非线性规划法求解减损与延寿控制律的过程。对发动机起动过程实施减损与延寿控制,结果表明在系统性能略微损失的情况下,可以较大幅度地减小涡轮叶片的损伤,从而达到延长发动机工作寿命的目的。     

基于云分类器的液体火箭发动机故障诊断方法

本文首先将液体火箭发动机故障诊断问题转化为故障特征的模式分类问题,然后针对当前模式分类方法难以处理不确定性信息、属性特征空间的划分过硬等缺陷,结合云模型和云变换研究,提出了一种基于云分类器的液体火箭发动机起动过程故障诊断方法。历次试车数据的验证结果表明,该方法能够及时准确识别发动机起动工作过程中的故障模式。     

基于迭代学习观测器的无人机故障鲁棒控制

针对无人机在飞行时存在执行机构故障和外界干扰问题,建立了无人机的动力学模型和系统发生执行器故障时的模型,提出了一种将迭代学习观测器和鲁棒自适应控制相结合的容错控制方法.利用迭代故障观测器去观测无人机控制系统的状态并通过迭代实时跟踪执行器故障,给出了该观测器的收敛性分析,并在此基础上设计基于自适应增益的趋近律,实现系统鲁棒自适应控制.进一步基于Lyapunov方法从理论上证明了设计的容错控制器的鲁棒稳定性.使用无人机控制系统对方法进行验证,仿真结果验证了方法的有效性.     

中国飞机真正有了“中国心”

经过18年的艰难跋涉,中国航空发动机研制实现了从中等推力到大推力的跨越;从涡喷发动机到涡扇发动机的跨越;从第二代发动机到第三代发动机的跨越     

以发展战略为龙头 促民用产业发展

经过四十多年的建设与发展,四川航天工业总公司逐步建立了以重大装备制造、综合与精密机械加工、控制制导设备、伺服机构与电液控制系统、涡喷发动机、火工装置、光电显示为特长的科研生产能力,形成了以战略武器批生产、竞争性战术武器和宇航产品研制生产、航天产品配套协作生产为主的军工产品科研生产体系。     

支板喷射超声速燃烧流场三维大涡模拟

利用火焰面模型和混合LES/RANS方法对某支板构型超燃冲压发动机进行模拟,讨论了化学反应对湍流流场的影响,并比较了3D和2D模拟的差别.结果表明,不考虑化学反应时剪切层中的大尺度结构控制着整个混合过程,且剪切层具有明显的三维特性;2D模拟能捕捉到涡的配对与合并现象,而3D模拟中涡的拉伸、扭曲及破碎特性更加显著;考虑化...     

北京动力机械研究所

北京动力机械研究所创建于1957年12月3日。经过几代飞航动力人的艰苦创业和半个多世纪的发展．北京动力机械研究所已经拥有吸气式发动机和火箭发动机、液体发动机和固体发动机等航天动力的自主创新、集成制造能力和完备的研制生产体系．实现了冲压发动机工程化、弹用涡喷涡扇发动机工程化系列化、中小型固体火箭发动机工程化系列化模块化和跨介质工作．成长为中国最大的航天动力产业之一。     

单组元姿控动力系统动态过程仿真研究

以单组元姿控动力系统为研究对象研究多台不同推力量级发动机工作时的动态过程.基于模块化建模,在MWorks软件平台上二次开发了包含液体管路、电磁阀、反应室等单组元姿控动力系统典型组件的动力学模型,搭建了动力系统中发动机起动、关机、脉冲工作等动态过程仿真模型,并通过试车数据验证了仿真模型的正确性与有效性.在单组元动力系统中...     

应用断裂力学方法分析涡喷—6发动机一级涡轮盘榫槽槽底裂纹

一、问题的提出及实际意义涡喷—6发动机用GH36合金钢制造的涡轮盘,使用中经常出现裂纹。修理过程中由于发现槽底裂纹超过了技术规定的1.5mm,使报废的一级涡轮盘达20％左右,造成很大损失。所以我们试图用断裂力学方法估计涡轮盘槽底裂纹的临界尺寸和对于使用一个寿命或若干寿命下的最大容许初始裂纹尺寸,以使裂纹的修理深度建立在更合理的基础上,以及放宽修理深度的规定,修改旧的修理规范,真正做到物尽其用。     

Volterra高阶核新算法在涡轮转速控制上的应用

给出了对非线性动态系统做任意精度逼近的Volterra级数高阶核的全新估算方法并将其应用于涡喷发动机的转速控制上。该方法在核函数理论基础上,构造线性空间,将求解Volterra级数各阶核的问题转化为求输出观测向量在希尔伯特空间中某一子空间上的投影的问题,使原本复杂的非线性系统的Volterra级数的逼近问题在线性空间中以向量内积的方式得到解决。与其他时域或频域估算Volterra核的方法相比较,该算法的优点在于理论体系严密、计算量不随阶数增高而成几何级数增加、辨识精度高。该方法理论上能够估算任意阶核,弥补了现有方法难以估算四阶以上核的缺点,可应用于动态系统和强非线性系统的建模。将发动机动态过程描述为四阶的Volterra级数模型。     

Putin – the masked nemesis of the strategy of ambiguity

Recent events demonstrate the complex and adaptive approach employed by Russia to reassert influence in Europe. The changing face of Russia’s strategy commenced in 2007 when it launched a crippling cyber-attack against Estonia. This was followed by a large Russian conventional attack against Georgia in 2008, occupying two large areas of the nation. 2014 witnessed the Russian annexation of Crimea where in just a week, Russia seized control of Crimea “without firing a shot.” The annexation of Crimea was rapidly followed by a Russian inspired and led subversive war in eastern Ukraine. The common thread among these diverse Russian operations is its use of ambiguity to confound and confuse decision makers in the West.     

India's counter-insurgency experience: the ‘trust and nurture’ strategy

The Indian Army, a force trained primarily for conventional warfare, has been engaged in internal counter-insurgency operations since the 1950s. Despite such a long innings on a counter-insurgency mode, little attention has been accorded within military circles to doctrinal innovation for waging sub-conventional warfare in India's democratic political context. At best, the Army continues to view counter-insurgency duty as secondary to its primary duty of defending India from external conventional threats. By conceptualizing a counter-insurgency strategy of ‘trust and nurture’, this article aims to fill this critical doctrinal gap in India's military policy. The author argues that a counter-insurgency strategy of ‘trust and nurture’ based on democratic political culture, measured military methods, special counter-insurgency forces, local social and cultural awareness and an integrative nation-building approach will result in positive handling of India's internal security problems. The author utilizes India's counter-insurgency experiences in Assam, Mizoram, Nagaland, Punjab, and Operation ‘Sadhbhavana’ in Jammu and Kashmir as illustrative empirical indicants in order to validate the ‘trust and nurture’ strategy.     

An Unlikely Alliance: Portuguese and South African Airpower in Angola, 1968–1974

The war that Portugal was obliged to fight in Africa began in 1961 and immediately stretched the resources of its armed forces. Nowhere was this thinness more apparent than in policing the vast territory of Angola. The east and southeast of Angola were particularly vulnerable, as the area was a vast, sparsely populated region characterised by enormous featureless plains or chanas covered in tall grass and broken by an extensive river system and mountainous forests. The only military solution to policing these immense spaces was aviation and specifically the helicopter that could carry troops into battle, protect them with a gunship and bring them home when the operation was concluded. The immediate problem for the Portuguese Air Force (Força Aérea Portuguesa or FAP) in Angola and elsewhere was a scarcity of helicopters. The solution was an alliance with South Africa, which had a strong inventory of Alouette IIIs, to help in policing the east. This move was likewise in the interest of South Africa, as its threat came from Zambia through south-eastern Angola. This article examines the strategic and tactical development of this unusual, cross-cultural alliance and the symbiotic relationship that resulted in destruction of the enemies of both in Angola.     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

国内外结构钢焊条研究的现状与发展

本文主要介绍了国外焊条的现状和发展趋势,包括焊条的高韧性、高效率、低尘低毒和耐吸潮性能,为国内的焊条研究提供了参考依据。     

A Sign of Victory?: ‘Scottish Swords’ and Other Weapons in the Possession of the ‘Auld Innemie’

Many late medieval documents, notably inventories of arms and armour, of Englishmen contain references to ‘Scottish swords’ and other weapons. What did the compilers of these documents mean when they described a weapon as ‘Scottish’? How did such weapons come to be in the possession of these men? This article will attempt to explain this phenomenon drawing on primary documentary sources and surviving material culture from Glasgow Museums’ collections and others, as well as artworks from the period.     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.