串联战斗部前后级作用关系数值模拟研究

利用Autodyn有限元软件采取三维数值仿真的方法,对串联战斗部前后级的作用关系开展研究。基于串联战斗部轴对称的特点,建立了1/2有限元仿真简化模型,通过设置前后级飞行速度0 m/s、100 m/s、200 m/s以及前后级间距10 mm、30 mm、50 mm,利用控制变量法,分析了前后级相对速度、前后级间距对随进子弹受力状态的影响规律。得出了随着前后级相对速度的增大或者前后级间距的减小,随进子弹各点的受力及速度降都会增大的变化规律。仿真结果可以为相关串联战斗部的优化设计提供参考。     

电磁发射高速旋转弹丸马格努斯效应

和传统火药发射弹丸相比,电磁发射弹丸具有初速高、射程远等优势,但尾部的电枢臂槽会使弹丸部流场不再轴对称,产生独特的气动力特性。基于三维非定常Navier-Stokers方程,采用滑移网格技术,分析电磁发射弹丸的气动力特性。研究表明,对于高速旋转的电磁发射弹丸,马格努斯效应来源于激波层内流场畸变和电枢臂的迎风面积变化的共同作用;电枢臂迎风面积的周期性变化是导致气动力和力矩周期性变化的原因,马格努斯力矩在滚转角45°和135°时分别达到最小值和最大值;电枢臂槽的存在既加剧了马格努斯效应(135°时增加50%以上),又使得压心周期性前移(绝对前移量达5%),并且随着转速的增加,马格努斯力矩增加和压心前移效果越来越显著,不利于弹丸的动稳定。     

Analysis of the mass of behind-armor debris generated by RHA subjected to normal penetration of variable cross-section EFP

Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30 mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered; 2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45° and the axial length of mushroom is considered.     

高原环境对弹丸动态稳定性的影响

分析了高原环境低空气密度对弹丸动态稳定性的影响。给出了弹道坐标系中的力方程组和非滚转弹体坐标系中的力矩方程组,并通过线性化方法得到弹丸角运动的状态空间模型。列出了角运动状态矩阵的四个特征根,并利用复数平方根计算方法得到特征根实部的表达式。提出弹丸动态稳定性稳定因子的新定义,并证明新的动态稳定条件与传统的动态稳定条件是一致的。讨论了低空气密度对尾翼稳定弹和旋转稳定弹动态稳定性的影响,并通过仿真说明弹丸在高原条件和平原条件下的动态稳定性存在差异。     

Effects of material of metallic frame on the penetration resistances of ceramic-metal hybrid structures

The effects of metallic material on the penetration resistances of ceramic-metal hybrid structures against vertical long-rod tungsten projectiles were studied by artillery-launched experiments and numerical simulation. Hybrid structures with rectangular cores in transverse orthogonal arrangement and slide-fitting ceramic inserts of zirconia toughened alumina prisms were fabricated with titanium alloy TC4 (Ti6Al4V), AISI 4340 steel and 7075 aluminum alloy panels, respectively. The results showed that the hybrid structure of Ti6Al4V exhibited the highest penetration resistance, followed by that of 7075 aluminum alloy with the same area density. The penetration resistance of the hybrid structure of AISI 4340 steel was the lowest. The underlying mechanisms showed that the metallic material of a ceramic-metal hybrid structure can directly affect its energy absorption from the impact projectile, which further affects its penetration resistance. Different metallic frames exhibited different failure characteristics, resulting in different constraint conditions or support conditions for ceramic prisms. The high penetration resistance of the Ti6Al4V hybrid structure was due to its stronger back support to ceramic prisms as compared with that of AISI 4340 steel hybrid structure, and better constraint condition for ceramic prisms by metallic webs as compared with that of 7075 aluminum alloy hybrid structure. The results of mass efficiency and thickness efficiency showed that the Ti6Al4V hybrid structure has advantages in reducing both the thickness and the mass of protective structure. In addition, because the ceramic-metal hybrid structures in the present work were heterogeneous, impact position has slight influence on their penetration resistances.     

Attitude deflection of oblique perforation of concrete targets by a rigid projectile

A perforation model is developed to predict the attitude deflection in the oblique perforation of concrete targets by a rigid projectile, in which the inertial moment of the projectile is introduced, together with taking the attitude deflection during the shear plugging sub-stage into account, and the shape of the plug formed on the rear surface of target is also re-investigated. Moreover, a new classification of concrete targets is proposed based on the target thickness, with which the attitude deflections in different kinds of concrete targets are analyzed. It is found that the numerical results by using the new perforation model are in good agreement with the previous experimental data and simulated results. Furthermore, the variations of the attitude deflection with the initial conditions (the initial attitude angle and the initial impact velocity) are investigated.     

穿甲子弹偏心入射陶瓷/钢复合靶板试验

设计并进行了7.62mm穿甲子弹侵彻陶瓷/低碳钢复合靶板的弹道试验,得到了极限速度及陶瓷锥底部半径等数据。分析了锥底半径与入射速度、面板及背板厚度的关系,着重分析了偏心入射时靶板的抗弹机理。结果表明:陶瓷锥可分为破碎区和粉碎区,粉碎区半径约为面板厚度与弹丸半径之和;当弹着点距离陶瓷面板边缘大于5mm时,靶板的抗弹性能变化不大,而弹着点位于距陶瓷面板边缘小于5mm的板边区时,抗弹性能明显降低,靶板的有效防护面积应扣除板边区。     

一种变质心高速旋转炮弹鲁棒姿态控制律

针对采用变质心技术的高速旋转炮弹的姿态控制问题,提出一种基于扩张状态观测器的动态面控制方法。根据由弹体和单滑块组成的多体系统的特点,建立了系统的姿态动力学模型,并对其进行了合理的简化。将系统的滚转通道引起的强耦合、建模误差及外部扰动等视为未知不确定干扰,并且考虑由于炮弹尺寸限制而引起的多体系统控制输入(滑块位移)的有限性,设计了扩张状态观测器和辅助系统,分别对系统的干扰进行观测以及处理控制输入的有限性,综合动态面控制技术设计了姿态控制律,最后基于李雅普诺夫稳定性原理证明了控制器的稳定性。仿真结果表明,该控制器能够在克服干扰的前提下快速稳定地跟踪指令信号,具有良好的控制精度和鲁棒性。     

基于PSO算法的脉冲修正弹控制参数优化*

针对脉冲修正弹自身控制离散不连续特征,开展了脉冲修正弹脉冲控制参数优化设计方法研究。考虑到脉冲成本和精度的双重要求,选择以脉冲发动机工作次数和脱靶量最少为双目标函数,并在风干扰的条件下,提出了以脉冲控制时间间隔为离散脉冲控制参数设计变量建立优化模型,以此发展了一种改进型递减惯性权重粒子群优化脉冲控制参数的方法,提高了修正参数优化收敛速度。仿真结果表明,该算法能快速有效地获得最优解,为在干扰条件下寻找最优的脉冲修正参数和脉冲工作方式提供了一种优化设计思路。     

火箭弹防静电作用研究

针对电发火弹药静电放电问题,以某型130 mm火箭弹为例,采用真实静电感度测试系统测试了电火工品在有、无绝缘层时50%的静电点火能量,并在试验程序及数据处理中使用真实静电感度数据处理方法统计了50%静电发火能量的估计值。通过比较发现二者的差值在误差范围内,这表明静电放电研究中可以将弹体所接受的能量视作全部作用于火工品上,绝缘层不吸收静电放电的能量。在电发火弹药的防护中,必须采用静电防护措施杜绝电发火弹药的意外发火。