Improving the damage potential of W-Zr reactive structure material under extreme loading condition

Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gun-powder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propa-gation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops the W-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.     

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.     

Zn-Al—Mg-RE高速电弧喷涂工艺过程的氧化行为分析

为分析高速电弧喷涂工艺制备Zn-Al-Mg-RE防腐涂层的氧化行为,通过XRD、SEM和EDS试验探究了喷涂工艺对该涂层氧化物的组成、含量及其形态的影响规律,并测试了涂层的中性盐雾腐蚀性能。结果发现：该涂层具有典型的层状结构特征,在相互叠加的扁平颗粒之间有很薄的氧化物膜,同时在扁平颗粒的内部也非均匀地分布着富氧化物区,XRD显示这些氧化物主要为ZnO2和尖晶石结构的ZnAl2O4与MgAl2O4等。分析认为：喷涂时液态金属熔滴在高速气流剪切力作用和反应热梯度作用下,加剧了Zn-Al-Mg-RE熔滴的氧化,这些交错分布的氧化物对合金相产生了较好的屏蔽效果,从而提高了涂层的耐蚀性能。     

基于群体协同的驱护编队中近程防空的系统效能

针对中近程反导的具体要求,分析了典型的驱护编队反导模式下编群队形特点,研究了指挥舰与护卫舰的队形关联性,探讨了基于信息化作战模式的抗饱和攻击能力,建立了基于多目标优化的最保守与最乐观情况下的抗饱和攻击模型,得到舰艇编队协同防空的系统效能,对驱护编队防空反导指挥决策具有很强的参考价值。     

复杂线型小水线面双体船兴波阻力数值计算方法研究

将分段幂多项式拟合方法与线性兴波阻力理论相结合,提出一种针对复杂线型小水线面双体船的兴波阻力数值计算方法,该方法应用于常规小水线面双体船的兴波阻力计算,表明该方法能在常规的幂多项式拟合方法的基础上进一步提高计算精度,同时也验证了该方法的正确性,将该方法的计算结果与复杂线型小水线面双体船剩余阻力的试验结果相比,两者吻合较好,证明了该方法用于复杂线型小水线面双体船的兴波阻力计算是可行的。     

中小型客车用钢──水热管式采暖装置工作温度控制研究

讨论了影响热管工作温度ｔｖ的主要因素,提出了控制钢──水热管工作温度（采暖装置的工作温度）的管长参数的确定原则,介绍了用于客车上的实例。     

基于梯度迭代法的一类追逃对抗模型研究

针对一类追逃对抗问题,基于微分对策理论,建立了三维空间中的追逃对抗模型,进而得到了最优性条件和最优策略.运用梯度迭代法给出了模型的数值解,并做了实例分析.分析结果显示,该模型可以很好地应用于潜艇对潜艇、潜艇对水面舰艇等实际追逃对抗问题.     

多孔介质中气体流量对流动阻力影响的实验研究

对空气在多孔介质(Pd/SiO2颗粒催化剂)中的流动阻力特性进行了冷态实验,研究了气体流量对流动阻力的影响.结果表明:催化剂厚度一定时,随着气体流量增大,多孔介质中的流动阻力也逐渐增大.经过与经典阻力计算公式对比,分析了偏差影响因素.最后,结合实验数据拟合出了适合管式反应器中流动阻力计算的半经验公式,能精确地预测颗粒填...     

穿浪双体船尾板减阻数值分析

基于RANS方程,采用RNG k-ε湍流模型和VOF两相流模型,研究了尾板长度与安装角度对穿浪双体船总阻力的影响规律.计算结果表明:尾板可以调整穿浪双体船的航态,达到有效降低阻力的目的;减阻在一定速度范围内有效,减阻的效果取决于尾板安装角度和长度,但阻力的减少并不与安装角度和长度成比例,最佳的安装角度约为3°～6°,长度约为1％～2％ LWL.     

潜艇内置隔板流体特性

为了探究隔板对隔舱特性的影响,以带流水孔潜艇内置隔板为研究对象,对潜艇内置隔舱设置不同的隔板数目,基于大涡模拟(LES)方法进行三维仿真模型进行数值模拟,分析内置隔板对潜艇隔舱阻力以及流噪声特性的影响。结果表明,内置隔板与流体的作用直接影响隔舱的整体特性。隔板数越多,隔舱阻力越大,噪声级也越高,并且阻力以及流噪声与来流速度呈正比例关系,这为潜艇内置隔板的设计提供了参考。