某动能防暴弹恒定落点动能弹道解算技术

为保证新型变初速动能防暴武器有效的执法效能和非致命效果,根据目标穿戴情况的不同,设定不同的能量打击等级.建立恒定落点动能弹道模型,运用Matlab和四阶龙格库塔对弹道模型方程组进行数值求解,得出了18.4 mm动能防暴弹,在100 m有效射程内,对10J,20J,30 J三种不同落点动能条件下,目标距离与弹丸初速度的匹配关系,并对终点速度波动量进行了分析.     

基于MATLAB的某大口径榴弹发射器的变初速分析

以某大口径榴弹发射器为例,对采用外加药室容积的变初速技术进行分析。利用内弹道原理对变初速方案进行建模;利用Runge-Kutta法,通过MATLAB软件进行变初速后的内弹道仿真。仿真结果说明了外加药室容积在不同位置时对弹丸初速的影响规律及影响程度,对变初速技术的工程应用具有一定的指导意义。     

超高速弹丸连续侵彻靶板仿真研究

试验验证超高速弹丸连续侵彻靶板时的侵彻效果代价过大,数值模拟预测提供了新的解决途径.建立了超高速弹丸与连续靶板模型,利用ABAQUS软件,结合Mie-Grüneisen状态方程、Johnson-Cook本构方程和Johnson-Cook断裂准则,对钨合金弹丸2km/s初速下连续侵彻钢质靶板进行仿真研究.超高速弹丸可连续侵彻6层厚度为30mm的靶板,相邻靶板受到了弹丸与飞溅单元的共同冲击,最后2块靶板主要受到飞溅单元的冲击.超高速弹丸每穿透一层靶板,头部及弹体表层发生着侵蚀变化、能量损失与速度变化.充塞穿甲是超高速动能弹的典型穿甲形式,穿甲威力大.数值模拟有助于认识超高速弹丸连续侵彻靶板的过程.     

气室装置对变威力发射影响分析

身管开孔泄气可以有效地调节弹丸初速实现变威力发射,身管开孔后通常加装气室装置对火药气体进行密闭或者通过气室装置引导火药气体排入大气。针对气室装置结构的不同,根据经典内弹道理论及气体动力学原理,建立了变威力发射过程的数学模型,通过数值仿真分析比较了两种不同变威力发射方案调速效果,得出了不同泄气孔面积对气室压力的影响规律,并研究了气室孔面积大小对初速的影响,研究结果对外置气室装置式变威力发射武器研制具有重要的指导意义。     

基于弹丸初速的火炮装药号辨识仿真

为了用弹丸初速来辨识火炮装药号,基于MATLAB建立了某型火炮的内弹道计算仿真模型,分析了火炮实际使用过程中变化参量如装药号、药室增长量、药温、弹重对弹丸初速的影响。研究表明,仅通过弹丸初速不能有效地对火炮装药号进行辨识。提出了基于弹丸初速、药温并考虑药室增长量变化阶段的火炮装药号辨识方案,基于仿真数据和人工神经网络建立了辨识模型,仿真试验表明,该模型对火炮装药号的辨识正确率达到100%。     

弹丸高速侵彻水介质的理论分析与数值仿真

弹丸在水中高速运动时涉及到复杂的流固耦合及多相流流体动力学问题,对于弹丸高速侵彻水介质的研究一直以来没有获得较大的突破。通过理论分析,给出了弹丸高速侵彻水介质的理论分析模型。并应用ANSYS/LS-DYNA软件,采用ALE算法对高速弹丸侵彻水介质过程进行了流固耦合的数值仿真计算。结果表明:该仿真模型有效解决了弹丸高速侵彻水介质时,由于流固耦合计算中流体形变引起的数值计算困难;弹丸初速越高,速度衰减越快,且变形越严重;衰减系数和阻力系数都随着弹丸初速的增大而增大。为弹丸高速侵彻水介质的理论分析和数值仿真研究提供有价值的参考。     

球径规值对角接触球轴承凸出量和接触角的影响

根据轴承内部滚动体与沟道的接触几何关系,推导了轴承实际凸出量的通用计算方法。在此基础上,针对实际生产过程两种操作方法(定游隙和变游隙),分析了滚动体直径变化对轴承凸出量和接触角的影响并推导了通用计算公式。研究表明,在定游隙情况下,滚动体直径变化对轴承凸出量和接触角的影响较小;而在变游隙情况下,上述影响较大。     

弹丸近炸破片密度分布与运动规律研究

针对靶场测试中弹丸炸点空间坐标难以获得及炸后碎片运动规律难以捕获的问题,分析了近炸弹丸炸后的碎片散布规律,研究了单发和多发弹丸炸后在弹目交汇平面上形成的碎片密度分布,阐述了弹丸炸后形成的破片运动,给出弹丸炸后形成的破片的速度衰减规律。通过计算与分析,将破片初速进行划分,给出破片速度衰减曲线,仿真结果显示当破片的初速和飞散距离都相同时,破片衰减之后的速度(存速)与单枚破片质量存在正比关系,破片质量越大则存速越大。     

角接触球轴承凸出量光学精密测量方法研究

角接触球轴承凸出量是轴向预载荷作用下轴承内外圈同一端面的距离,是精密角接触球轴承配对使用的依据。 为实现 角接触球轴承凸出量快速精密测量,提出了一种光学精密测量方法并研制了测量装置。 通过更换不同尺寸轴承定位爪,可实现 7208C、7208AC、7308B、7408B 轴承凸出量的测量。 分析了轴承套圈和滚子之间的赫兹接触,揭示了轴承凸出量变化量与轴向载 荷之间的关系,轴承凸出量变化趋势随轴向载荷增加而变缓,逐渐趋向于线性相关。 基于有限单元法对测量装置的机架和内圈 驱动分别进行变形分析和简谐振动分析,优化后传感器测头振动幅值减小到 0. 029 μm。 以 7008C(P2)为试验轴承,进行轴承 凸出量测量试验。 验证结果表明,其测量精度达到 0. 5 μm,实测样件偏差小于 0. 2 μm。     

弹丸炮口初速的智能测量

本文介绍一种弹丸炮口初速的智能测量方法,给出了测量原理、硬件构成、软件设计和误差分析。     

Characteristics and measurement of supersonic projectile shock waves by a 32-microphone ring array

This paper discusses about the characteristics of supersonic projectile shock wave in muzzle region during firing of high explosive anti-tank (HEAT) and high explosive (HE) projectiles. HEAT projectiles are fired horizontally at a muzzle velocity of Mach 3.5 from a medium caliber tank gun equipped with a newly designed multi-perforated muzzle brake, whereas HE projectiles are fired at elevation angles at a muzzle velocity of Mach 2 from a large caliber howitzer equipped with a newly designed double-baffle muzzle brake. In the near field, pressure signatures of the N-wave generated from projectiles are measured by 32-microphone ring array wrapped by cotton sheath. Records measured by the microphone array are used to demonstrate several key characteristics of the shock wave of supersonic projectile. All measurements made in this study can be a significant reference for developing guns, tanks, or the chassis of fighting vehicles.     

电磁发射中初速测量的初步分析

从电磁发射的基本特点出发,对各种典型的区截测速方法进行了分析和对比,并结合实际应用中的三区截靶测速法,给出了基于匀变速假设的炮口初速外推公式和精度分析;结合现代科学技术和先进测试技术的发展,给出了对应于当前超高速发射中的电磁轨道炮炮口初速测量的一些讨论和建议。     

Further studies of the oblique impact of a hard sphere against a ductile solid

The impact of hardened steel spheres against ductile mild steel targets has been studied both theoretically and experimentally. It is shown that a relatively simple computer model based on the assumptions that the sphere is rigid and the target an ideal rigid-plastic solid provides a surprisingly successful explanation of the observed variation of crater volume and projectile energy loss with impact angle and velocity. This model also explains satisfactorily the measured rebound velocity for oblique impact, but cannot account for the finite rebound velocity observed under normal impact conditions. Rebound angles also are under-estimated.     

双管火炮异步发射时膛口流场分析

采用计算流体力学方法结合动网格技术建立了双管火炮异步发射时膛口流场的二维数值模拟模型,正确描述了双管不同步发射时炮口流场的激波系结构的形成﹑发展与相互干扰的过程。模拟结果得出双管不同步发射时对弹丸飞出膛口后的飞行姿态影响较大,从而弹丸偏移速度会影响双管火炮的射击精度。     

Analysis of initial velocity measurement methods of projectile muzzle

Because of the influence of conventio n al ammunition working in high rotation,high overloading,high temperature,hig h pressure and other harsh environments during the launch,it is difficult to m easure the initial velocity of projectile muzzle.This paper analyzes and compar es each sort of characteristics of several ty pical initial velocity measurement methods of projectile muzzle both at home and abroad,and proposes the development trend based on current research and practi cal aplication.     

Plasma enclosed in a magnetic field produced by flexible surface magnets

A homogeneous steady state plasma with a usable volume of approximately 200 l and with an electron temperature of 1-2 eV and a plasma density of approximately 10(9)-10(10) cm(-3) is produced in a discharge chamber the outside of whose walls is covered with flexible magnetic strips. This magnet arrangement can be built at a fraction of the cost of a conventional system using rigid surface magnets. The magnetic multipole field leads to an increase of the plasma density by one to two orders of magnitude and it is also found to cause trapping of high energy electrons originating from the discharge region.     

机枪枪架结构改进及其动力学特性分析

以某型重机枪为研究对象,在不改动枪身的前提下对弹性三角枪架进行了改进研究。采用ADAMS/Autoflex模块,建立基于刚柔耦合多体系统动力学的机枪虚拟样机模型,并求解出其在连发状态下的动力响应。所得结果与原有三脚架进行了分析比较,证明了改进型三脚架的优越性。     

飞秒激光精修面齿轮的扫描烧蚀特征控制

基于飞秒激光精修面齿轮时的能量累积效应,建立了光子-电子-晶格系统间耦合作用的三温传热模型,提出一种确定飞秒激光烧蚀齿面扫描路径间扫描间距的方法。仿真得出,能量密度为6.47 J/cm2时,平衡温度3200 K超过材料的熔化温度,热累积效应明显。根据不同的扫描间距计算激光累积强度,以控制凹坑烧蚀深度和轮廓。实验结果显示,能量密度为6.47 J/cm2时,随着扫描间距的减小,激光累积强度增大,齿面的烧蚀深度线性增大;扫描间距为25 μm时的齿轮表面加工质量良好。     

Effects of concentrated rigid inclusions defects on the in-plane impact behavior of hexagonal honeycombs

Hexagonal honeycombs have exhibited significant advantages in energy absorption and they are increasingly used as absorbers under crush conditions. The in-plane crushing process of imperfect hexagonal honeycombs with concentrated rigid inclusions defects is simulated using finite element simulations. In each case, a constant velocity is applied to an impact plate which then crushed the honeycomb. Simulation results indicate that the defect location has a great influence on the deformation modes, especially at low and moderate velocity. After analyzing the apparent reflection about dynamic response at the impact end, the respective influences of local fraction of inclusions and foil thickness (relative density) on the crushing plateau stress on account of the crushing velocity are further discussed. Furthermore, the energy absorption capacity under constant velocity loading is studied. Due to the distribution of the concentrated rigid inclusions defects, the energy absorption can be controlled effectively.