侵彻弹内电火工品的射频安全性分析

为研究射频对侵彻弹内电火工品的影响,按照电火工品射频安全性评价方法,在RFID手持设备终端(频率:927MHz,天线增益:4d B,发射功率:0~30d Bm连续可调)辐射电磁环境中,对该侵彻火箭弹中的3种电火工品安全性进行测试。测试结果表明该侵彻火箭弹最小安全无隐患电场强度为9V/m。当发射功率在20~30d Bm范围内,设备终端与电火工品的距离不小于0.20m时,EED1和EED2均表现为射频辐射安全;当发射功率在20~22d Bm范围内,设备终端与电火工品的距离不小于0.20m时,EED3表现为射频辐射安全。     

Experimental review of metallurgical flash weld defects in welded joints: essence of flat spots,penetrators and oxide inclusions

Abstract

Typical flash weld defects are divided into metallurgical and mechanical defects. The metallurgical defects, which also include defects known as flat spots, penetrators and oxide inclusions, are difficult problems and develop during flashing action. The appearances and differences of flat spots, penetrators and simple oxide inclusions in flash welds are determined in this study based on literature review and experimental studies with three different steel grades. It was concluded on the basis of experimental studies that the chemical compositions of flat spots and oxide inclusions are the same, and the main difference between them is their appearance: flat spots are fracture surfaces nucleated from oxide inclusions, but simple oxide containing slags can appear also in non-fractured surfaces.     

刚性球体对理想刚塑性靶体的定常侵彻

本文对刚性球体侵彻理想刚塑性无限靶体的定常侵彻问题进行了有限元分析.假定靶体服从Von-Mises曲服准则及相应的流动法则.并且假定靶体和侵彻体之间是光滑接触.文中主要介绍了有限元分析的整个过程并对计算得到的速度场进行了讨论。     

Behind-armor debris from the impact of hypervelocity tungsten penetrators

Behind-armor debris is the main mechanism by which targets are destroyed by projectile impact. The behind-armor debris generated from the impact of tungsten heavy alloy (THA) penetrators with a length-to-diameter ratio (L/D) of 20 against 6061-T6 aluminum targets was characterized. Behind-armor debris characteristics described were the number of debris particles, their positions, and their size distribution. Experiments were performed against two nominal target thicknesses, 100 and 150 mm, and covered a velocity range from 1.7 to 2.6 km/s. Two methods of obtaining data were used—radiographs were taken of the behind-armor debris, and perforation patterns were generated on steel witness packs placed behind the aluminum target. Debris particles recovered from the witness packs were also studied. Results are discussed for the effect of changes in target thickness and impact velocity on behind-armor debris particle characteristics.     

两种典型双层EFP战斗部数值模拟及试验研究

采用数值仿真与试验研究相结合的方法.为了进一步提高EFP战斗部侵彻钢靶目标的深度,设计了由铝-铜和铝-铁组成的两种典型双层EFP战斗部装药结构,并利用有限元软件LS-DYNA对这两种不同材料制成的复合型爆炸成型弹丸药型罩进行了数值模拟,然后配以相应的炸药装药进行试验研究,并对两种研究结果进行了简要的分析.结果证明,在双...     

钨药型罩材料的研究进展

钨具有高的密度和较高的声速,是一种良好的药型罩候选材料,高声速有利于获得高速粘性头部射流,并且对破甲弹射流的迅速拉长起至关重要作用。本文综述了从钨药型罩中获得有效延性射流方面所取得的进展,同时也指出射流过程有限元数值计算的重要性。     

RETRACTED ARTICLE: Penetrator strength effect in long-rod critical ricochet angle

3D numerical simulations were performed in order to further investigate the role of penetrator strength in the interaction of long-rods and oblique targets. Three distinctive regimes resulting from oblique impact depending on the obliquity, namely simple ricochet, critical ricochet and target perforation, were investigated in detail. Critical ricochet angles were calculated with a full 3D explicit finite element method for various impact velocities and strength of target plates and projectiles. Numerical predictions were compared with existing two-dimensional analytical models and test results. It was predicted that critical ricochet angle increases with decreasing impact velocity and that higher ricochet angles were expected if higher strength target materials are employed. But there are differences between analytical models and 3D numerical simulation results or test results. The causes for these discrepancies are established by numerical simulations which explore the validity of the penetrator strength parameter in the analytical model as a physical entity. As a matter of fact, in this paper we first investigate the role of penetrator dynamic strength using two-dimensional simulation which resulted in different penetrator strengths out of different impact velocities. Next, by applying these amounts for penetrator strength in Rosenberg analytical model the critical ricochet angle is calculated. Finally, a comparison between the present analytical method with the 3D simulation and test results shows that the new analytical approach leads to modified results with respect to Rosenberg ones. This paper was recommended for publication in revised form by Associate Editor Jeonghoon Yoo Kamran Daneshjou, is University Professor at Iran University of Science and Technology. He studied his MSC and PhD at aeronautical Engineering de-partment of Imperial college of Science and Technology in London. His own research is at the interface of solid mechanic, finite element and electromagnetic lunchers to address the sustainable development of aerospace and solid mechanic projects. His publications include 7 books and over 100 scientific papers. This article has been retracted due to copyright issues that cannot be resolved.     

注射成形钨合金弹芯材料的性能与组织特征

研究开发低成本钨合金的近净成形技术是钨合金的一个重要发展方向。针对直径较大(Φ20～25mm)的钨棒弹芯和钨环散弹弹芯材料的注射成形,对粘结剂进行一系列的改进。采用一种粘度适中、流动性好、流变稳定性好的油+少量蜡组成的新型半固态塑料体系粘结剂,和多组元低分子混合溶剂快速脱除注射坯中60％以上的粘结剂,再采用热脱脂脱除其余的粘结剂,然后烧结,制备了性能很高的钨环和钨棒弹芯材料。研究了弹芯材料的性能和组织特征。结果表明,由弹芯加工成的冲击试样断口和拉伸试样断口形貌呈显著的钨晶粒穿晶解理断裂。采用注射成形工艺可以得到具有较高综合力学性能的钨合金弹芯。对于大截面的钨棒弹芯,弹芯材料的拉伸性能、延伸率和冲击性能分别达到σ_b=965MPa,δ=23％,A_k=54.4J/cm~2。     

侵彻武器用MEMS大g值加速度计

侵彻武器穿入地面等坚硬物质的加速度可达重力加速度的2万倍至几十万倍,要求所用加速度传感器既能抗击该工作环境,又能识别冲击与钻入的整个过程.美国侵彻武器用MEMS大g值加速度计属电容传感器,其工作原理采用2个电参数完全相同的电容,1个作检测电容,1个作参考电容,将被测加速度值的变化转换成电容量的变化而实现.该加速度计由结构单元和信号处理电路组成.实验结果表明,尚需对2组成部分进一步集成,对机械静电阻尼进行优化,对封装深入研究.     

侵彻子弹在机场跑道中的爆破实验研究

为研究侵彻子弹对机场跑道的毁伤效果,进行了侵彻子弹在各级机场跑道中的爆炸实验.实验结果表明,侵彻子弹在各级实验靶中最佳炸深时的破坏效果由大到小依次为沥青靶、二级靶、一级靶、特级靶;根据实验结果拟合得到炸深与爆坑半径的关系曲线,拟合曲线呈抛物线状,并得到可用于工程计算的公式;此外,拟合出单位炸深时爆坑半径与装药量的关系曲线.研究结果为侵彻子弹的引信设计提供了依据.