抛索火箭系统主动段绳索动力学特性研究

针对抛索火箭系统主动段绳索复杂的动力学特性,建立了基于多体动力学方法的绳索模型;数值仿真了真实火箭推力作用下绳索主动段飞行动力学过程及其动态特性。研究结果表明:主动段绳索运动呈波动状态,绳索速度和绳索内张力呈现规律性波动,随着编号增加,速度波动幅度先增大后减小,绳索内张力波动的幅度和大幅波动持续时间先减小后增大,绳段最大速度达到325.42 m/s,绳段内张力的峰值达到了8 162.5 N。仿真计算结果与试验数据较一致,该研究成果对抛索火箭系统绳索选择和系统弹道设计有参考价值。     

绳索对抛索火箭弹道特性的影响

抛索火箭系统的绳索动力学问题十分复杂.采用有限段方法对绳索进行建模,分析推导了绳索的运动和受力,根据Kane方法选择了合适的广义坐标,建立了拖缆火箭飞行的动力学模型.利用该动力学模型分析了绳索对抛索火箭弹道特性的影响,得到了绳索线密度、空气阻力系数对射程、速度、弹道倾角等弹道特性影响规律,为下一步研究绳子对拖缆火箭飞行的扰动以及拖缆火箭制导控制提供了理论模型和指导.     

抛索火箭平面运动弹道模型研究

抛索火箭的运动是变质量变结构变边界条件的复杂动力学问题。根据牛顿—欧拉方程,采用集中质量法建立了抛索火箭运动模型。将绳索离散为一系列质量集中在一点的单元,并假设绳索上所有的作用力都集中作用在集中质量点上。通过火箭运动方程、绳索各单元的运动方程、绳索间约束方程和边界条件,联立求解抛索火箭的运动方程。对抛索火箭进行了运动仿真,仿真结果与试验结果一致性较好。该运动弹道模型可以为工程设计提供理论指导。     

远程火箭末敏弹弹道特性仿真

为研究远程火箭末敏弹弹道特性,应用弹道理论和控制理论,建立了远程火箭末敏弹母弹弹道方程;引入多体系统动力学理论,分析了末敏弹系统伞、伞盘、弹等刚体间的力学关系,考虑了系统的连接方式和约束,分析了伞绳弹性,建立了末敏弹在减速运动和稳态扫描段的完整运动模型.编制了远程火箭末敏弹弹道仿真软件,进行了末敏弹全弹道数字仿真,并得到了部分试验验证,分析了末敏弹弹道特性.为远程火箭末敏弹射击精度仿真和减少精度试验用弹量奠定了基础.     

带鸭舵滑翔增程炮弹飞行弹道研究

文中针对鸭式布局的滑翔增程炮弹的飞行弹道特性,通过动力学分析,建立了滑翔增程炮弹的各飞行弹道段的弹道模型和控制模型,数值分析给出了滑翔增程弹飞行速度变化规律、最大射程角以及滑翔增程炮弹的滚转控制段与滑翔控制段的弹道特性,研究结果为鸭式布局滑翔增程炮弹的弹道设计提供了理论基础。     

由火箭一级飞行弹道分析底部力等动力参数

以某液体火箭一级飞行为例,分析火箭在穿越大气飞行段所受到的综合外力情况;通过建立力学模型,完成对发动机推力及大气阻力等飞行参数的弹道特征辨识。分析结果表明,该液体火箭存在随飞行高度变化的附加底部力。     

火箭拖拽布撒网系统建模与动力学分析

布撒网系统利用火箭拖拽将网体布设至目标区域、完成雷区清障任务,研究其展开动力学过程,对系统设计有着重要的理论指导意义。基于刚体动力学及多体系统动力学中的集中质量方法,分别建立了火箭及柔性布撒网块的三维动力学模型,给出了系统动力学方程。利用4阶 Runge-Kutta法解算系统动力学方程,通过数值模拟计算分析了布撒网飞行布设准确性的影响参数。通过集中质量模型与多刚体模型对比,分析二者仿真结果中的火箭弹道、质心速度和俯仰角等关键动力学参数,研究了火箭拖拽布撒网系统的基本飞行动力学特性,得出集中质量模型的准确性更高。根据工程实际研制出火箭拖拽布撒网系统的试验样机,并完成了样机的场地飞行试验。结果表明：数值计算与试验结果吻合良好,系统布设到位率达到90%以上。     

火箭拖拽布撒网飞行轨迹研究

对布撒网系统纵向展开问题进行了研究。研究采用二维运动模型简化,运用多体系统动力学理论和集中质量法,建立了布撒网纵向展开过程的多刚体动力学模型。运用Kane方法建立系统动力学方程,运用数值方法分析和计算了该动力学方程,给出了布撒网纵向展开的动力学过程。得到了火箭和网上各点位置和受力的时程曲线,以及火箭和网的飞行轨迹。计算结果与模拟布撒网展开实验结果吻合。     

火箭助飞鱼雷作战弹道仿真系统

为火箭助飞鱼雷的弹道仿真研究提供有效的平台,根据火箭助飞鱼雷全弹道运动流程,建立了其空中和水下的动力学、运动学、控制导引及风场环境等模型,应用面向对象方法设计了仿真模型,构建了仿真系统。对典型态势进行仿真,得到了全弹道曲线和特征点处战技指标参数,结果表明所建模型正确,仿真系统具有良好的可操作性。     

超远程火箭弹道设计研究

根据射程,运载火箭一般可分为近程、中程、远程和洲际运载火箭,射程超过地球周长一半的火箭一般称为超远程火箭.当前,超远程火箭的弹道方案主要采取高弹道、部分轨道等技术,具体实现方案包括直接飞行、弹道主动段机动飞行、弹道被动段机动飞行、近地圆轨道机动飞行、近地椭圆轨道机动飞行等 5 种技术方案.对方案可行性及方案选择的判断依据进行研究,分析各技术方案的弹道特点,并与标准洲际射程参数进行对比,为超远程火箭的弹道技术方案的选择提供了借鉴.     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Design and Implementation of One Missile Visual Simulation System Based on OpenGL

The implementation of a missile＇s visual simulation system is explained that is developed with OpenGL（open graphic library） and the flight path and flight carriage in different stages of the missile are displayed. The establishment problems of the 3D scene are circumstantiated including the construction and redeployment of the model, creation of the virtual scene, setting of the multi-viewports and multi-windows etc. The missile＇s data driver, system flow, the modules and their mutual relations of the missile visual simulation system are discussed. The missile flight simulation results and effect of the scenes are given.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Dynamic Encryption Technology in Ad-hoc Networks

A new dynamic encryption application in ad-hoc networks is proposed. The advantages of this method are its being able to use the previous ciphertext as a seed of a new encryption process, rendering the encryption process effective in all communication process by continuous dynamic key generation together with synchronization, and its capability to cut back on system bandages to a greater extent, which is valuable for the ad-hoc circumstance. In addition, the rationality and effectiveness of this novel encryption method have been verified by the test results.