Influence of thickness and projectile shape on penetration resistance of the compliant composite

The present study deals with development of conceptual proof for jute rubber basedflexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element (FE) method. The proposed flexible composite blocks of repeating jute/rubber/jute (JRJ) units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat (F), ogival (O) and hemispherical (HS) shaped projectiles. All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied. The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Tagu-chi's design of experiments (DOE). Results reveal that the though proposedflexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile, considering the safety issues, it is recommended to use theflexible composite with thickness of 120 mm. The nature of damage caused by the projectile in the flexible composite is also studied. Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite.     

改善机载前向阵雷达全程检测性能的研究

针对前向阵的杂波分布特性 ,给出了一种空时自适应处理 (STAP)结合多重中脉冲重复频率(MPRF)的处理方案 ,研究了重复频率的选择以改进系统性能 ,并分析计算了三路多普勒通道联合处理STAP方法在一组中脉冲重复频率下的改善因子和距离 /速度二维盲区分布图。理论分析与仿真结果表明 ,该方案可以大大改善机载前向阵雷达的全程检测性能     

平面动载实验中碰撞速度和倾斜度测试的一个方法

平面动载实验中 ,飞片碰撞速度和碰撞状态是加载条件的一个基本描述。本文采用电探针技术 ,给出了一个同时测得真实飞片速度和碰撞倾斜状态的探针排布设计。此设计用于化爆产生平面动载的氮化硅粉体冲击波活化研究 ,取得了较为理想的测试结果。     

水压场信息处理系统

介绍了以３８６型微机为核心,由微压差传感器、传感器平衡及实时标定装置、直流放大器、Ａ／Ｄ转换器、站位控制电路构成的实验室用模型水压场信息处理系统．     

稳像火控中目标角速度测量误差及滤波方法

对稳像火控系统中目标角速度的测量过程进行了分析,指出采用自动传感器测量目标角速度仍存在误差,且对射击诸元的影响较大;在计算机采集数据的有限时间段内,该误差序列为均值不为零的随机干扰噪声,采用均值—中值加权滤波方法可有效减小该嗓声对射击诸元影响.     

材料压剪加载的实验测试

利用Ｙ—切石英晶体的各向异性动态响应材料特性,实现对粘接在石英晶体后表面的材料试件的一维平面复合压缩剪切加载。用电磁质速法测试试件中不同位置上的质点在压剪加载下的运动情况。从处于粘接界面上的量计所测纵向质速史和横向质速史,可以看到压剪波传入试件中的清晰的两波（ＱＬ波,ＱＴ波）结构,与理论估计基本相符;其它位置上量计的测试曲线亦反映了材料对压剪波传播的动态响应特点,可以看到剪切波的衰减规律。     

Kane方程在平面机构动力学中的应用

在平面机构动力学的研究过程中,因其含有闭环结构而使得经典动力学的应用遇到许多麻烦。本文采用近几年发展起来的Kane方程对此进行了研究,给出了任意的平面机构的动力学方程和与之对应的数值计算方法,所得结果程序化。为平面机构的动力学控制与仿真提供了有效的方法。同时使Kane方程得以运用到新的领域。     

130mm加农炮剩余寿命的一种预测模型

本文根据火炮寿命试验数据,利用给出的模拟曲线的误差调整控制方法,建立了以炮膛定点径向磨损量预测初速变化量和剩余寿命的数学模型。     

海用跟踪雷达轴线角速度测量

讨论了一种伺服设计方案的雷达轴线角速度的测量方法。给出了三个不同的测量点,并说明在稳态条件下,从这三个点测量到的结果都可当作目标视线角速度,且误差不大。最后还给出了测量值的暂态计算机模拟结果。     

Experimental investigation on anti-penetration performance of polyurea-coated ASTM1045 steel plate subjected to projectile impact

In this study, the anti-penetration performance of polyurea/ASTM1405-steel composite plate subjected to high velocity projectile was analyzed. Two kinds of modified polyurea material (AMMT-053 and AMMT-055) were selected and a ballistic impact testing system including speed measuring target system and high-speed camera was designed. This experiment was conducted with a rifle and 5.8 mm projectile to explore the effects by the polyurea coating thickness, the polyurea coating position and the glass-fiber cloth on the anti-penetration performance of polyurea/ASTM1405-steel composite plate. The result showed that the effects of polyurea coating position were different between two types of polyurea, and that the effects of glass-fiber position were disparate between two types of polyurea as well. For AMMT-053 polyurea material, it was better to be on front face than on rear face; whereas for AMMT-055 pol-yurea, it was better to be on rear surface although the difference was very subtle. Additionally, formulas had been given to describe the relationship between the effectiveness of polyurea and the thickness of polyurea coating. In general, AMMT-055 had better anti-penetration performance than AMMT-053. Furthermore, five typical damage modes including self-healing, crack, local bulge, spallation and local fragmentation were defined and the failure mechanism was analyzed with the results of SHPB test. Additionally, the bonding strength played an important role in the anti-penetration performance of polyurea/steel composite plate.