Critical interfaces in body armour systems

The ballistic performance, and behaviour, of an armour system is governed by two major sets of variables, geometrical and material. Of these, the consistency of performance, especially against small arms ammunition, will depend upon the consistency of the properties of the constituent materials. In a body armour system for example, fibre diameter, areal density of woven fabric, and bulk density of ceramic are examples of critical parameters and monitoring such parameters will form the backbone of associated quality control procedures. What is often overlooked, because it can fall into the User’s domain, are the interfaces that exist between the various products; the carrier, the Soft Armour Insert (SAI), and the one or two hard armour plates (HAP1 and HAP2). This is especially true if the various products are sourced from different suppliers.There are between 30 and 150 individual layers within a typical body armour system, and each of the interfaces between each of those layers will, in some way or another, contribute to the ballistic performance of the system. For example, consider the following interfaces/interlayers: (i) the frictional, sliding, inter-ply surfaces within a soft armour pack, and also between the pack and the carrier, (ii) the air-gaps that may develop within the soft armour pack, (iii) the interconnecting space between the soft armour pack and the hard armour plate, (iv) the nature of the interfaces between adjacent plies of a multiplied backing laminate, even in a highly compressed Ultra High Molecular Weight Polyethylene (UHMWPE) variant, (v) the interlayer between the ceramic and its substrate, within a HAP, and (vi) the geometrical fit between two hard armour plates within a stacked body armour system. This paper will provide a User-friendly overview of all such interfaces and provide unique guidance as to their criticality and influence.     

俄海军面临第五次复兴

第二次世界大战后,苏联经过40多年的发展,形成了一只可以和美国在全球争霸的远洋作战海军。苏联解体后．由于俄罗斯经济长期萧条．俄罗斯海军也面临着前所未有的严峻局面。1989年苏联的造船工业共为其海军制造了78艘潜艇、作战舰艇及勤务舰船,而1995、1996、1997年俄罗斯海军分别只有11、8、6艘新造舰艇服役,到了1999年则只有4艘。     

Mechanical stress and deformation analyses of pressurized cylindrical shells based on a higher-order modeling

In this research, mechanical stress, static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented. The kinematic relations are developed based on higherorder sinusoidal shear deformation theory. Thickness stretching formulation is accounted for more accurate analysis. The total transverse deflection is divided into bending, shear and thickness stretching parts in which the third term is responsible for change of deflection along the thicknes...     

Assessment of the ballistic response of honeycomb sandwich structures subjected to offset and normal impact

In the present study, experimental and numerical investigations were carried out to examine the behavior of sandwich panels with honeycomb cores. The high velocity impact tests were carried out using a compressed air gun. A sharp conical nosed projectile was impacted normally and with some offset distance(20 mm and 40 mm). The deformation, failure mode and energy dissipation characteristics were obtained for both kinds of loading. Moreover, the explicit solver was run in Abaqus to create the fin...     

An energetic nano-fiber composite based on polystyrene and 1,3,5-trinitro-1,3,5-triazinane fabricated via electrospinning technique

Electrospinning is a simple technique used to fabricate polymeric nano-fibrous membranes. These nano-fibers have found a wide range of valuable applications in the biomedical field. However, it has not been utilized with solid high explosives yet. Herein, the electrospinning technique has been used to fabricate polystyrene(PS)/1,3,5-trinitro-1,3,5-triazinane(RDX) composite nanofibers. The governed electrospinning parameters, voltage, distance from the collector, flow rate, mandrel rotating speed...     

印度的核原则

核威慑只有在应对核武器的使用以及大规模传统进攻时才能发挥作用。这就让印度的战略决策者不得不接受这样一个现实：核武器其实并不是用来使用的。也不能像获取领土和控制人口一样达成任何战略目标;而且其大规模的潜在杀伤力加上其导致基因突变需要几代人来消除其影响的能力。基本上已经决定了任何一方都不会主动使用它的性质。     

跟踪系统的计算机辅助设计

本文介绍利用系数平面模型、回路波德图及二阶示性函数最小化技术实现跟踪系统人—机对话计算机辅助设计的方法。应用经典示性函数,将设计方案直接与适当的现行工程设计相联系,重点放在系数平面的通用区。结合具体实例,用示意图说明在系统发生变化的情况下,应用硬件反馈装置可减小性能的变化。利用观测器,以状态变量为基础的等效设计不会减小性能的变化。采用最小平方误差算法,可实现与性能指标相适应的低阶补偿器。     

低成本技术提供一种精确的脱靶距离指示

一种雷达脱靶距离指示器已经研制成功,它用多普勒频率来确定弹丸脱靶距离的大小。防空导弹和火炮部队的实践训练化费极大。因而采用训练模拟器日益增多。但是它们不能提供对实靶射击的实际训练的机会。     

常规威慑的新技术

加强北约的常规作战能力已成为连任的里根政府优先考虑的问题。作为一种防止核军事冲突升级的方法,它依赖于研究一种所谓“新技术”(Emerging Technology,以下简称ET技术)来建立常規武器系统,以遏制苏联的非核攻击。美国已接受了空地战原则来发展这些技术,而北约已接受了“攻击后续力量”(follow-on-iorce attack,FOFA)原则,它可应用ET技术来延伸通向敌后的战场。据说这两种原则是相互协调的,但并非完全一致。空地战原则从属于美国的全球战略。与之相配合的FOFA原则关心的只是欧洲纵深战场。在下面的文章中,美国负责常规作战的国防部副部长助理James Tegneia博士阐明了这种美国新战略的原理,它的结构变化以及与之有关的硬设备情况。(有关它的武器系统详细说明见IDR,8/1984,PP,1053～1066)