An experiment evaluating how the tiny mass eccentricities in spin-stabilized projectiles affect the position of impact points

This study investigates and quantifies some possible sources affecting the position of impact points of small caliber spin-stabilized projectiles (such as 12.7 mm bullets). A comparative experiment utilizing the control variable method was designed to figure out the influence of tiny eccentric centroids on the projectiles. The study critically analyzes data obtained from characteristic parameter measurements and precision trials. It also combines Sobol's algorithm with an artificial intelligence algorithm—Adaptive Neuro-Fuzzy Inference Systems (ANFIS)—in order to conduct global sensitivity analysis and determine which parameters were most influential. The results indicate that the impact points of projectiles with an entry angle of 0° deflected to the left to that of projectiles with an entry angle of 90°. The difference of the mean coordinates of impact points was about 12.61 cm at a target range of 200 m. Variance analysis indicated that the entry angle — i.e. the initial position of mass eccentricity — had a notable influence. After global sensitivity analysis, the significance of the effect of mass eccentricity was confirmed again and the most influential factors were determined to be the axial moment and transverse moment of inertia (Izz Iyy), the mass of a projectile (m), the distance between nose and center of mass along the symmetry axis for a projectile (Lm), and the eccentric distance of the centroid (Lr). The results imply that the control scheme by means of modifying mass center (moving mass or mass eccentricity) is promising for designing small-caliber spin-stabilized projectiles.     

Influence of a liquid-filled compartment structure on the incoming shaped charge jet stability

Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compart-ment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet sta-bility is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the re-sidual jet are obtained.A theoretical model is validated against the experimental penetration depths.     

某型延期传扩爆装置爆速偏高质量改进

延期传扩爆装置作为一种新型组合式火工品,其性能对战斗部最终发挥作战效能起到至关重要的作用。本文从建立影响导爆索爆速的故障树入手,分析了原材料、拉索模具、加工工艺、测试方法等因素对爆速的影响,解决了产品延期时间偏高的质量问题。     

航空用复合材料结构件无损检测技术分析

本文通过对航空复合材料结构件缺陷和损伤特点的分析,介绍可应用于航空复合材料结构缺陷包括目视检查法、声阻法、射线检测技术、超声检测技术、声-超声技术、涡流检测技术、微波检测技术在内的无损检测技术。并对无损检测技术的技术关键进行剖析,展望了无损检测技术的未来发展。     

立足军队的职能使命,提高抓军事斗争准备的本领

提高领导军事斗争准备的本领,抓紧做好军事斗争准备是我军各级党组织面临的最重要、最现实、最紧迫的战略任务。正确认识各级党组织的根本领导职能,正确把握军事斗争准备的内涵和定位,是增强各级党组织抓军事斗争准备自觉性、减少盲目性的必要前提。提高各级党组织抓军事斗争准备能力要重视的是:它涉及到诸多因素,必须着力研究和解决制约能力提高的各种问题;它是一个复杂的系统工程,既需要各级党组织自身的努力,又需要多方面形成合力。     

三组元推进系统热力性能研究

随着下一代可重复使用飞行器，特别是单级入轨飞行器的研究，很多新技术都得到发展，三组元混合燃烧技术就是其中之一。本文中通过进行热力计算来对比、讨论三组元发动机与两组元发动机在理论比冲上的差异，分析三组元发动机的可行性。     

弹性地基上的压杆横向振动频率方程的一般表达式

推导出弹性地基上的等截面受压直杆横向振动频率方程的一般表达式。在杆的各种端点条件下进行了分析和讨论     

利用PB 6.0实现数据库动态查询

在分析关系数据库SQL查询语言原理的基础上,通过一个具体的例子介绍了如何利用PB6.0实现数据库动态查询.     

飞船轴对称热化学非平衡流场数值求解

本文从轴对称热化学非平衡Ｎ－Ｓ方程出发,利用时间相关法,采用双温度、七组元反应气体模型,利用隐式ＮＮＤ有限差分格式和时间预处理技术数值求解了ＦＩＲＥＩ飞船热化学非平衡流场,得到了较为准确的结果,并分析了热力非平衡对流场的影响。     

舰船交流电力系统短路电流的改进算法及计算软件的编制

针对中国国家军用标准方法（ＧＪＢ－１７３）在计算某型舰船电力系统短路电流时误差较大的情况,提出了一种新的具有较高计算精度的短路电流计算方法——改进算法．提供了一套用ＶｉｓｕａｌＢａｓｉｃ５．０编制的短路电流计算软件,该软件具有良好的人机对话能力和友好的界面,使用方便,且有较强的通用性