偏头控飞行器气动仿真与外形优化

针对智能偏转弹头的飞行器模型,以通用流体计算软件FLUENT为计算平台,进行了大量气动仿真实验.计算了不同头部偏角,不同马赫数和攻角姿态条件下,智能偏转弹头模型所受的气动力;分析在不同条件下升力、阻力和偏航力矩的变化情况,同时比较了不同外形的此类弹头的气动特性。仿真结果表明在飞行速度大于一个马赫的情况下,大长径比、尖锥外形的智能偏转弹头可获得较大的升阻比和偏航力矩,气动性能较好。     

弹头外形对非零攻角亚音速旋转弹丸气动特性的影响

为寻求阻力特性受攻角影响较小的弹丸外形,提高射击精度,针对35 mm 口径亚音速旋转稳定弹丸,利用FLUENT 软件仿真研究半球形、抛物线形、截锥形三类弹头外形对非零攻角亚音速旋转弹丸气动特性的影响,并借助Matlab 软件模拟亚音速范围内弹丸阻力系数 Cx 随攻角 x 的变化规律,计算得到弹丸攻角系数 K 值在16～20;结果表明：半球形弹头外形对非零攻角亚音速旋转弹丸气动特性的影响较小,而抛物线形弹头外形对亚音速旋转弹丸阻力系数的影响较小;用于描述弹丸阻力系数 Cx 随攻角变化规律的函数 Cx ＝cx2＋dx ＋e 相对函数 Cx ＝ax2＋b 更为精确,相对误差前者小于1％,后者小于4．5％。     

偏转弹头导弹气动特性研究

利用计算流体力学(CFD)方法对偏转弹头控制导弹和鸭舵控制导弹在不同马赫数、攻角和控制面偏角等状态下的流场进行数值模拟,并对两者的阻力特性、升力特性和俯仰力矩特性等气动特性进行了比较分析。得出偏转弹头控制具有气动性能好、控制效率高、机动性强等特点,其控制效率随着马赫数的增加而增加,是导弹高速飞行过程中快速响应控制的理想方式。     

大口径枪弹弹头外形优化与气动特性

为提高大口径枪弹飞行稳定性和射击密集度,对大口径枪弹弹头外形优化与气动特性进行研究。以12.7 mm 机枪弹弹头为对象,建立弹头3 维造型,定量分析其弧形部半径、弧形部长度、船尾角度和船尾长度,结合数值模 拟获取弹头飞行过程中的压力云图和阻力系数的变化曲线,提出优化后的弹头外形参数,得出外形变化对弹头气动 特性的一般影响规律。仿真结果表明：该研究能优化弹头外形设计,对大口径枪弹弹头外形设计及气动特性具有一 定的参考价值。     

再入体气动参数的神经网络辨识方法

以某弹头六自由度数学模型为基础,介绍了飞行数据的产生及神经网络算法选择和学习步骤．采用RBF网络增长型结构训I练算法对某型号弹头再入段动力学模型的气动参数进行了辨识,用优化初始化权值的方法解决了训I练时间长的问题．仿真结果表明该方法是可行的．     

一种偏转弹头控制系统方案研究

偏转弹头控制是一种新型的快速响应控制技术,与传统的舵控制不同,它具有高机动性、控制响应时间短、良好的气动特性等优点.根据一种弹头偏转机构方案,对偏转弹头控制系统进行了研究,建立了一种简单、合理的偏转弹头控制系统方案,通过坐标转换推导出弹头偏转控制规律;初步研究了偏转弹头控制导弹的气动特性,并与传统的舵控制导弹进行了比较,计算结果表明,偏转弹头导弹具有更高的控制效率,且在高超声速条件下,仍然维持较高水平.     

再入机动弹道气动环境仿真研究

机动弹头再入飞行时．其控制系统是由空气舵偏转产生的空气动力作为控制力的．文中研究了空气舵三个通道之间的交连耦合影响并建立了再入机动弹道的气动环境模型。通过仿真试验，结果证明文中建立的模型与机动弹头再入飞行的实际情况更为接近．验证了模型的可信性。     

弹头部圆弧曲线的气动设计

文中应用数值仿真软件对某弹头部的三种设计方案进行了外流场数值仿真,在仿真结果的基础上对弹头部气动参数进行对比分析,得出了较优气动外形.从而验证了外流场数值仿真方法是弹箭气动外形设计的一种快速、高效的方法,相对风洞实验,具有设计效率高,研制成本低的优点.     

一种新型触针式三维弹头痕迹检测系统

介绍了一种新研制的触针式三维弹头痕迹检测系统的原理、结构、控制以及实验结果。该垂直分辨率为０．００５μｍ，测量范围６ｍｍ，圆分辨率５０＂，轴向分辨率为１．２５μｍ，可以完整地获取弹头发射痕迹的直实形状。     

新概念伸缩舵面机动弹头布局初步研究

提出了一种伸缩舵面机动弹头气动布局设计的新理念,避免了普通全动舵面布局方案中舵轴设计面临的严峻热环境和力环境等问题.初步研究了采用这类设计理念的多种机动弹头布局的气动特性,分析了伸缩舵面机动弹头布局的稳定和操纵特性,对采用这种理念设计得到的一种机动弹头布局的机动性能进行了仿真.结果表明,新的机动弹头有较强的机动性,可通过机动飞行增大突破敌方导弹防御体系的概率,并能明显增加射程.     

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.     

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.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Overview of Anti-tank Mines

First the different anti-tank mines laying possibilities are shortly summarized： hand emplaced, with mine layers, ground or helicopter relatively topographical well defined, and with cluster systems of projectiles, rockets and aircraft dispensers. Then examples of the three generations of anti-tank mines are presented：Ⅰ generation： detonating only beneath the track; Ⅱ generation： detonating beneath the track and belly; Ⅲ generation： mines with off-route actions. Weight and cost comparisons are strongly favoring the off-route Ⅲ-generation mines.     

A Finite Element Analysis on Static Strength of a Complex Section

A static finite element analysis （FEA） of an impulsive controller section is presented. The boundary condition and a part of the loads are applied. Considering the grades of the stress around the holes being large, the dense grids are adjusted accordingly. Four cases with different loads are compared, thus the influences of different loads on the section are analyzed. Numerical results show that the maximum stress of the section is lower than the strength limit of the material, and the section will not be broken with the static loads.     

Discussion on Mechanism of Breech-Blow Caused by Propellant Charge

From the view point of launch safety caused by fracture of propellant charge, this paper points out that the safety criterion of pressure wave is inadequate to evaluate the launch safety of propellant charge based on the initial negative differential pressure and sensitivity tests. Generally, the maximum barrel pressure does not depend upon the intensity of pressure wave correspondingly. The pressure wave intensity can not describe the fracture degree of propellant charge in chamber and reflect the mechanical environment of propellant charge fracturing exactly and wholly. The evaluation criterion for launch safety of propellant charge should be built on the basis of depicting the fracture degree of propellant bed.     

Experimental Studies of Toxicity on HNIW and Its Intermediates

The polycyclic nitramine hexanitrohexaazaisowurtane（HNIW） is a compound of high energy density. HNIW can replace 1, 3, 5-trinitro-1, 3, 5-triazacyclohexane（RDX） or HMX, hut its toxicity is unknown. In this paper, HNIW, hexabenzylhexaazaisowurtzitane （HBIW）, tetraacetyldibenzulhexaazaisowurtzitane （TADBIW）, tetraacetyldiformylhexaazaisowurtzitane（TADFIW） and tetraacetylhexaazaisowurtzitane（TAIW）, which are intermediates of the synthesis of the HNIW, were selected as the tested objects in acute toxicity test, acute eye stimulation test and skin irritation test according to the standards of ＂chemical product testing method-401 ： acute oral toxicity test＂, ＂chemical product testing means-405： acute eye irritation/corrosion test＂ and ＂chemical product testing means-404： acute dermal irritation/corrosion test＂ of National Circumstance Protect Bureau. The results show that all of the five objects have no toxicity, no stimulation to eye and skin under the tested conditions.     

Dynamic Simulation for Missile Erection System

In order to study the dynamic characteristics of the missile erection system, it can be considered as a rigid-flexible coupling multi-body system. Firstly, the actual system is abstracted as an equal and simplified one and then the forces applied to it are analyzed. Secondly, the rigid-flexible coupling dynamic simulation for erection system is accomplished by use of the system simulation software, for example Pro/E, ADAMS, ANSYS, MATLAB/Simulink, etc. Finally, having the aid of simulation results, the kinetic and dynamic characteristics of the flexible bodies in erection system are analyzed.The simulation considering the erection system as a rigid-flexible coupling system can provide valuable results to the research of its kinetic, dynamic and vibrational characteristics.