脱壳弹弹托分离的双目视觉测量

脱壳弹的弹托分离过程对弹体的飞行稳定性和打击效能具有显著的影响。针对脱壳弹出膛后弹托相对弹体的六自由度运动过程,提出采用基于双目视觉原理的弹托分离角测量方法。通过在弹体表面和弹托表面设置标记点,采用图像处理和跟踪算法实现对标记点的识别和跟踪。结合双目空间标定参数解算出标记点的空间位置,进而获得弹托相对弹体的分离角度,同时采用实验验证了上述测量方法的精度,其精度达到2%。以实验室进行的初速度1 550 m/s和1 750 m/s的脱壳弹射击试验为例,测量并分析了不同初速度下的弹托分离轨迹。结果表明:脱壳弹分离初速度越快,弹托分离轨迹越靠近弹体。     

电磁发射弹丸飞行弹道仿真

针对电磁发射弹丸飞行弹道进行仿真研究，在建立刚体六自由度飞行弹道模型的基础上，采用时频分析和涡流分析方法，建立电磁-动力学耦合模型分析弹丸出膛时由于膛内振动带来的炮口扰动，采用动网格技术建立电磁-气动耦合模型分析弹托分离产生的气动扰动，从而得到了电磁发射弹丸的飞行弹道模型。以得克萨斯大学先进技术研究所设计的IAT-HVP为例，仿真分析了弹丸以1117 m/s初速、0°射角出膛时弹丸出口扰动对弹体速度和气动特性的影响，并得到其飞行200 m的弹道曲线。仿真结果表明，受电磁发射一体化弹丸出口扰动的影响，弹体落点相比理想弹道产生了24%的偏差，其中炮口扰动引起的偏差最大，其次是弹托分离。     

某型近距格斗导弹数字仿真

针对某型近距格斗导弹的特点,建立了导弹六自由度动力学方程、目标运动方程、导弹状态方程、导弹推力矢量与气动力复合控制模型和大气环境模型,在此基础上,通过数字仿真计算了一定条件下该弹的攻击区.     

激光制导航空炸弹三维动态数字仿真研究

以某型激光制导航空炸弹为例,进行了三维动态数字仿真研究,文中建立了该型激光制导炸弹六自由度空间运动方程和双通道控制系统模型。通过仿真计算,得到了该弹的三维攻击区,并将三维动画技术应用于实时仿真系统的软件开发中     

横向运动板对长杆弹侵彻的偏转作用

弹体的攻角直接影响其侵彻能力,而横向运动板能使弹体发生偏转改变攻角,间接影响弹体的侵彻能力。在一定条件下,推导长杆弹在单层横向运动板作用下的偏转模型,并利用有限元仿真软件ANSYS／LS-rDYNA对长杆弹侵彻横向运动板的过程进行数值模拟。通过对偏转模型及仿真结果的分析,发现两者较为相符。研究结果显示：长杆弹侵彻横向运动板时,弹体会发生偏转,偏转的角速度先增后减,最后为0rad／s,此时偏转角最大;弹体速度方向也会发生偏转,其最终偏转角与弹体轴线的偏转角接近。     

超音速子母弹时序抛撒分离干扰特性

为分析在时序抛撒方式下子母弹多体干扰流场特性及其对各舱段弹体气动特性的影响,基于流体控制方程与六自由度刚体运动方程,结合非结构动网格技术,分别对两种时序抛撒方式及后舱子弹单独抛撒方式下的子母弹三维非定常分离流场进行数值模拟,得到不同抛撒时序下的分离流场特性及其气动干扰特性,揭示各舱段子弹在不同分离阶段的气动干扰相互作用过程。研究结果表明:在时序抛撒分离过程中各弹体间激波不断地交错干扰,增加了流场结构的复杂性;前舱子弹的激波干扰使得后舱段子弹气动分离参数较低,分离效率较慢,尤其在短时序间隔下,后舱弹体受前舱子弹干扰较为严重,弹体的安全分离受到影响。     

子母弹结构特征对分离特性影响分析

超声速下子母弹的分离过程是一种包括多体运动边界与复杂气动流场干扰的多体分离问题。采用嵌套网格技术,对流体力学方程组及六自由度刚体动力学方程组进行了耦合求解,重点研究了子母弹的结构特征(包括子弹的数目、有无弹翼及排列方式等)对分离过程中流场特性的影响。结果表明:嵌套网格技术能较好地模拟超声速子母弹分离过程中的复杂扰动流场;子弹体数目越多,弹体间的气动耦合效应越强;尾翼的存在能够极大提高弹体的静稳定性;相较于"圆周型"分布,"中心圆周型"分布趋于加快弹体间的分离。     

无人机配载弹射式导弹静稳定性分析

通过刚体飞行六自由度动力学方程建立弹射式导弹初始段无控飞行模型,并结合弹射装置动力模型和导弹发动机推力模型进行仿真计算。基于无控飞行模型和仿真结果分析了无人机配载弹射式导弹发射特性,在导弹初始飞行段对机弹分离安全性和导弹姿态控制要求进行了研究。对导弹不同静稳定度下的运动特性对比分析,分别给出了满足各种安全和控制要求的导弹静稳定度范围。进一步综合所有安全和姿态控制要求,得到了满足所有要求的最佳静稳定度。经过一个实例的仿真研究,结果表明建立的模型与所用到的方法是合理有效的。     

采用遗传算法的弹托迎风窝结构设计

针对一体化弹丸弹托易分离性和轻质化的设计要求，构建弹托迎风窝参数化外形模型，基于激波和膨胀波理论建立弹托气动力计算模型；以弹托分离加速度和弹托质量综合最优为目标函数，采用遗传算法对弹托迎风窝的外形参数进行优化设计，从而得到弹托迎风窝的优化外形。以中口径尾翼稳定脱壳穿甲弹的弹托设计为例，采用提出的优化设计模型对其迎风窝结构进行优化设计，并采用基于动网格技术的弹托分离仿真模型验证其最优性。仿真结果表明：所提优化模型能够得到最优的弹托迎风窝结构；针对现有的中口径尾翼稳定脱壳穿甲弹，可进一步对其弹托结构进行优化，以提高其分离快速性。     

二维弹道修正弹控制特性分析与仿真

旋转稳定弹丸的高速滚转使修正控制过程中的俯仰平面和偏航平面的弹体运动特性存在很强的交联,使得弹丸修正时控制信号与弹丸运动方向有滞后偏差。为解决修正弹控制响应相位滞后,首先从理论上推导出影响控制响应相位角的公式,运用四阶多项式拟合出了控制相位角与马赫数之间的关系。最后通过固定控制角的有控仿真,验证了拟合出控制响应相位角的正确性,并得出在该弹进行弹道修正时,应在上升段采取横向修正,下降段综合修正的结论。     

大口径穿甲弹用材料应用研究动态及分析

为了提高穿甲弹的威力,有效对抗新型防护装甲和防护技术,对现有提高大口径穿甲弹穿甲威力的技术途径进行了分析,得出了弹芯材料和弹托材料的力学性能是制约穿甲威力提高的关键因素。详细阐述了目前国内外在大口径穿甲弹用弹芯材料的强韧化、绝热剪切敏感性,新型复合材料弹芯的研究和轻质弹托材料的应用研究动态,并对研究中存在的问题进行了分析。最后,对我国大口径穿甲弹用材料的研究工作进行了展望。     

某型穿甲弹弹托轻量化仿真研究

为了减小弹托消极质量,提高某型穿甲弹的威力,运用Ansys11.0软件的Workbench平台,采用瞬态动力学方法对某型穿甲弹的发射强度进行了仿真,结果表明:该弹弹托马鞍部和尾椎部的强度裕度较大。通过在马鞍部钻孔和尾椎部开槽,在满足发射强度要求的前提下可减轻弹托质量170 g,从而使该型穿甲弹的炮口初速提高了16.25 m/s,进而使该型穿甲弹对既定目标的有效穿透距离增加了270 m左右。     

Electronic warfare in the optical band: Main features,examples and selected measurement data

The paper presents the possibilities of, and methods for, acquiring, analysing and processing optical signals in order to recognise, identify and counteract threats on the contemporary battleground. The main ways electronic warfare is waged in the optical band of the electromagnetic wave spectrum have been formulated, including the acquisition of optical emitter signatures, as well as ultraviolet (UV) and thermal (IR) signatures. The physical parameters and values describing the emission of laser radiation are discussed, including their importance in terms of creating optical signatures. Moreover, it has been shown that in the transformation of optical signals into signatures, only their spectral and temporal parameters can be applied. This was confirmed in experimental part of the paper, which includes our own measurements of spectral and temporal emission characteristics for three types of binocular laser rangefinders. It has been further shown that through simple registration and quick analysis involving comparison of emission time parameters in the case of UV signatures in “solar-blind” band, various events can be identified quickly and faultlessly. The same is true for IR signatures, where the amplitudes of the recorded signal for several wavelengths are compared. This was confirmed experimentally for UV signatures by registering and then analyzing signals from several events during military exercises at a training ground, namely Rocket Propelled Grenade (RPG) launches and explosions after hitting targets, trinitrotoluene (TNT) explosions, firing armour-piercing, fin-stabilised, discarding sabots (APFSDS) or high explosive (HE) projectiles. The final section describes a proposed model database of emitters, created as a result of analysing and transforming the recorded signals into optical signatures.     

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).     

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.     

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.