叠层顺序对双层A3钢薄板抗侵彻性能的影响

在轻气炮上进行了卵形头、平头及半球形头杆弹正撞击等厚接触式双层靶的实验,得到了这几种 结构的剩余速度-初始速度曲线及弹道极限速度,研究了叠层顺序对靶体抗侵彻性能的影响。实验表明:叠层 顺序对双层靶体抗侵彻性能的影响与弹体头部形状密切相关。对于平头和半球形头弹,厚板在前、薄板在后 的靶体的弹道极限速度高于相反叠层顺序的靶体的弹道极限速度;但是对于卵形头弹,薄板在前、厚板在后的 靶体的弹道极限速度高于相反叠层顺序的靶体的弹道极限速度。叠层顺序对靶体弹道极限速度的影响主要 通过改变靶板的失效形式和靶板间的作用力实现。     

A3钢钝头弹撞击45钢板破坏模式的试验研究

为了研究破片模拟弹的终点弹道效应,进行了不同质量A3钢钝头弹(弹径25 mm)撞击45钢板的试验研究,其中A3钢强度弱于45钢。在约200～800 m/s的撞击速度范围内,随着撞击速度的增加,分别观察到弹体出现泰勒撞击、向日葵型花瓣帽形失效及靶板冲塞穿甲三种破坏模式。伴随弹体和靶体经历的不同结构破坏模式,弹材和靶材也经历着相当复杂的材料失效。     

12.7mm动能弹斜侵彻复合装甲的数值模拟研究

通过弹道枪实验对斜置角度为0°～60°的陶瓷复合装甲进行了弹道极限测试，分析了靶板斜置角度对穿燃弹的弹道极限和钢芯质量变化、破坏形态的影响。利用数值模拟的方法对上述实验结果进行验证计算，鉴于数值计算结果与实验结果较好的一致性，进一步研究了陶瓷复合靶板斜置角度对穿燃弹钢芯穿靶偏移角和等效Q235钢靶厚度的影响。结果表明，随陶瓷复合靶板斜置角度的增大:弹道极限近似指数型提高；在相同弹道极限速度下，穿燃弹对Q235钢靶板的极限穿深和对斜置陶瓷复合靶板的极限穿深的等效厚度的比也随之增大；同时，钢芯完整度逐渐降低，穿靶偏移角反向增大。     

A3钢钝头弹撞击45钢板破坏模式的数值分析

不同速度范围内的A3钢钝头弹撞击45钢靶板分别表现为泰勒撞击、向日葵型花瓣帽形失效和靶板冲塞穿甲等3种不同的破坏模式,利用LS-DYNA对这种复杂的破坏机理和相应的影响因素进行了数值模拟研究。采用Johnson-Cook强度模型和累积损伤失效模型描述弹靶材料的力学性能,并考虑了塑性变形的绝热温升效应。数值模拟再现了不同破坏模式的失效过程,得到了与实验一致的结果。研究还指出,弹靶的冲塞穿甲实际是在高速撞击下,弹体发生花瓣帽形变形失效后继续穿甲靶板的后续结果。     

撞击姿态对构型弹体非正侵彻多层间隔钢靶弹道特性的影响规律

为深入认识构型弹体非正侵彻多层间隔靶板的弹道偏转规律，结合数值模拟和理论分析，研究了构型弹体在不同撞击姿态下侵彻多层间隔钢靶的弹道特性，其中引入弹体侧向接触力和侧向偏转力矩等参量，着重分析撞击着角和攻角对弹道特性的影响规律。结果表明：构型弹体非正侵彻过程中，在纵向发生阶梯式速度衰减，但变化较小；同时，由于穿靶过程中受到侧向接触力及其偏转力矩的作用，在侧向产生显著弹道偏转。撞击着角决定弹体所受外载荷的非对称程度，着角越大，弹体偏转越严重；撞击攻角则主要影响弹肩穿靶时的径向速度和弹尾穿靶时的触靶位置，二者共同影响弹道轨迹，因而存在使弹体偏转程度发生转折的临界攻角。相比于侵彻单层靶，构型弹体非正侵彻多层间隔靶板的显著特点为弹道偏转存在累积效应，且侵彻前一靶板的弹道偏转情况显著影响到侵彻后一靶板时的弹靶作用特征，进而导致弹道偏转与弹靶接触力互相耦合。相关研究对预测构型弹体侵彻多层间隔靶板性能、优化弹体构型和撞击姿态等具有较好的指导价值。     

弹靶尺寸对陶瓷/金属复合装甲防护性能的影响

利用Autodyn软件开展数值模拟工作,对陶瓷/金属复合装甲的防护性能与弹靶尺寸的关系进行研究。首先,建立二维轴对称SPH-Lagrange模型,并利用实验数据验证模型有效性;在此基础上对不同几何参数的弹靶撞击进行数值模拟,分析靶板厚度、靶板平面尺寸、子弹长度等对氧化铝陶瓷/铝合金复合装甲弹道极限速度的影响规律。然后,通过量纲分析,提出装甲弹道极限速度与弹靶几何参数的量纲一关系式,并在数值模拟结果的基础上建立一个装甲弹道极限速度的经验公式。     

钨球对高硬度钢斜侵彻效应

为研究高硬度钢板抗不同着角钨球的侵彻性能及破坏模式,通过弹道枪进行了?8 mm、?11 mm钨合金球形破片以0°、20°、40°着角撞击厚度为6 mm、8 mm的高硬度钢板试验,得到了极限贯穿速度v₅₀;分析了钨球轴向径向变形及靶板失效模式与撞击速度的关系,发现高硬度钢板失效模式主要为压缩开坑破坏和沿厚度方向剪切破坏。采用有限元方法对试验进行了模拟,验证了数值模型及参数的合理性,并运用数值模拟方法研究了撞击着角对靶板吸能模式影响,结合试验数据,修正已有极限贯穿速度计算公式。结果表明:随侵彻着角增大,极限贯穿速度提高,且着角越大,极限贯穿速度增长越快;随着角增大,靶板吸能模式逐渐由压缩开坑向剪切冲塞过渡,且着角大于50°时,剪切冲塞耗能将超过压缩开坑耗能;修正后极限贯穿速度计算公式适用范围更广、精度更高,具有较好工程应用价值。     

带前舱物的钝头弹对金属靶的正穿甲分析

进一步发展了考虑结构响应的剪切冲塞模型,计及前舱物的作用,对带前舱物的钝头弹穿甲金属靶的工程问题进行了刚塑性分析,用于分析终点弹道极限和剩余速度。除剪切破坏之外,模型还考虑了靶板弯曲、膜力拉伸和前舱物撞击引起的靶板预结构响应等。给出了简洁的终点弹道性能公式,与相关实验结果较吻合。     

钢筋混凝土穿甲的数值模拟

比较了LS-DYNA中关于钢筋和混凝土相互作用的不同处理方式（即接触方法和耦合方法）对钢筋混凝土穿甲结果的影响。数值模拟S.J.Hanchak 等关于钢筋混凝土靶的穿甲实验,给出了弹靶的变形破坏过程。讨论了穿甲钢筋混凝土靶的撞击位置对终点弹道性能的影响,加深了钢筋对侵彻作用的认识。所确定的数值模拟方法可用于进一步讨论钢筋结构与尺寸、配筋率等参数对侵彻影响等问题的研究。     

装甲钢/UHPC复合靶体抗侵彻性能试验与数值模拟研究

装甲钢/超高性能混凝土（UHPC）复合防护结构在重点工程中抵抗弹体的高速侵彻作用具有广泛的应用前景。为评估该复合结构的抗侵彻性能,对两种复合靶体开展侵彻试验与数值模拟研究。首先,开展了12发30 mm口径30CrMnSiNi2A弹体372~646 m/s速度侵彻复合靶试验。随后通过一系列静动态力学性能试验标定装甲钢材料的本构模型参数,并建立三维有限元模型对上述试验开展数值模拟分析。通过对比试验和数值模拟得到的弹体侵彻深度、残余弹体长度和装甲钢板的失效模式,验证了装甲钢本构模型参数的可靠性。进一步基于弹道效益系数对复合靶抗侵彻性能进行了定量评估。最后,确定了不同装甲钢板厚度复合靶体的临界贯穿速度,并对弹体侵彻复合靶的弹、靶失效模式进行了讨论。     

On the ballistic resistance of double-layered steel plates: An experimental and numerical investigation

Civil and military ballistic protection systems often consist of thin, high-strength steel plates. Such plates may either be monolithic or layered with or without spacing. The idea of using layered plates instead of a monolithic one in order to increase the ballistic perforation resistance is not new, and the effect of using targets made up of several thinner plates has been investigated in the literature for a long time. However, results by various authors are contradicting and detailed experimental and numerical work is still required.In the present study, the ballistic perforation resistance of double-layered steel plates impacted by blunt and ogival projectiles was investigated both experimentally and numerically. In the tests, 12 mm thick (monolithic or layered) targets of Weldox 700 E were impacted using a gas-gun at sub-ordnance velocity, and the ballistic limit velocity of the different target combinations was obtained. In general, good agreement was obtained between the numerical simulations and the experimental results. It was found that in the case of blunt projectiles a large gain in the ballistic limit is offered by double-layered systems. These advantages seem to disappear when ogival projectiles are used. However, the main conclusion from both the experimental and numerical studies is that the overall protection level, i.e. the minimum ballistic limit velocity obtained independently of projectile nose shape, seems to increase significantly by double-layering the target.     

Effect of projectile nose shape,impact velocity and target thickness on deformation behavior of aluminum plates

The present study deals with the experimental and numerical investigations of aluminum target plates impacted by blunt, ogive and hemispherical nosed steel projectiles. The projectiles were normally impacted on the target plates of 0.5, 0.71, 1, 1.5, 2, 2.5 and 3 mm thicknesses at different velocities with the help of a pneumatic gun. Effect of projectile nose shape, impact velocity and plate thickness on the deformation of the target plates was studied. Hemispherical nosed projectile caused highest global deformation (dishing) of the target plates. Ogive nosed projectiles were found to be the most efficient penetrator for the case of plates of thicknesses 0.5, 0.71, 1.0 and 1.5 mm. For the case of plates of thicknesses 2.0, 2.5 and 3.0 mm however, blunt nosed projectiles required least energy to perforate the target plates. The ballistic limit velocity of hemispherical nosed projectiles was found to be highest as compared to the other two projectiles. Finite element analysis of the problem was carried out using ABAQUS finite element code. Results of the numerical analysis were compared with the experiments and good correlation between the two was found.     

Behaviour of uniaxially preloaded aluminium plates subjected to high-velocity impact

The purpose of this paper is to evaluate the behaviour of structural thin plates made of 7075-T6 aluminium alloy under normal impact of spherical steel projectiles, when they are subjected to uniaxial in-plane tensile preload. Also, nonloaded plates were tested under high-velocity impact. The impact and residual velocity were measured in all tests. From the relationships between the impact and residual velocities, the ballistic limit was estimated by a least-squares method. No significant differences were found between the ballistic limits under the two loaded conditions. Above the ballistic limit in the preloaded plates, unstable cracks that can generate the catastrophic failure of the plate were observed. At similar velocities, this phenomenon was not observed in nonloaded plates.     

刚性钝头弹体正冲击GH4169间隔靶的消耗功分析

在380～680 m/s的弹体初速范围内，开展了直径8 mm钨球正冲击GH4169间隔靶实验，测得弹体初速、余速及靶板形貌，明显看出第1层板挠度较小,主要表现为剪切破坏，并产生了杯状挤凿块，第3层板挠度较大，主要表现为拉伸破坏。提出了间隔靶消耗功计算公式，结合剪切冲塞模型和建立的挤凿块速度模型计算了刚性钝头弹体冲击间隔靶中各层板的消耗功。结果表明，第2～3层板的单位面密度消耗功远高于相同面密度的第1层板，这与各层板的变形和失效形式密切相关。消耗功分析可用于定量描述间隔靶中各层板的抗侵彻性能。     

厚壁压力管道侧向冲击破坏的实验研究

本文报导了三跨连续压力管道侧向受平头、半球头及锥头弹体冲击破坏的实验研究结果,管的外径为45mm,厚度为3mm,内充液体压力分别为0MPa,5MPa,10MPa,15MPa和20MPa五级,获得了不同工况下的临界破坏速度及相应的破坏模式,实验过程中测量并记录了圆管的变形、冲击力时程曲线。实验结果表明,内充介质的存在降低了临界破坏能量,同时临界破坏能量随内充介质压力的增加而减小。     

充液金属圆柱壳受弹体冲击的整体变形与局部破坏分析

在地基梁类比方法基础上,建立了一组充液金属圆柱壳受平头弹体侧向正冲击的理论分析模型,该模型可以确定冲击过程圆柱壳的整体变形及弹性的穿透破坏,利用该模型计算了弹道极限速度,弹体及圆柱壳的冲击响应历程,特别地,分析了内压对弹道极限速度等参数的影响,得到了内压与弹道极限速度的关系帮一些有意义的结论,理论结果与已有实验结果基本吻合。     

The global deformation and local damage analysis of filled metallic cylindrical shells impacted by missiles

A group of theoretical models has been developed for analyzing transient dynamic response to filled metallic cylindrical shells impacted by flat-nosed missiles at normal obliquity on the basis of the analogy modeling method of beam-on-foundation. It can be used for solving the global deformation and the local failure of cylindrical shells in the impact process. The ballistic limit speed and impact response history have been calculated by this group of theoretical models, and the inner pressure effect on the ballistic limit speed and some parameters are discussed at length. The quantitative relationship between internal pressure and the ballistic limit speed and some significant conclusions have been obtained, which are basically identical with previous experimental results. Project supported by Shanxi Natural Science and Returnee Foundations (no. 971004)     

刚性尖头弹垂直撞击金属厚靶板极限速度分析

研究了刚性尖头弹垂直撞击金属厚靶板扩孔冲塞型和延性扩孔型穿孔模式,提出分析最小穿透能量的两阶段工程模型．应用功能原理和圆柱形空腔膨胀理论得到第一阶段侵彻扩孔耗能．考虑靶板背面自由边界的影响,应用Taylor扩孔理论计算延性扩孔型穿孔第二阶段耗能;考虑加速塞块和剪断塞块所损耗的能量,由动量和能量原理导出扩孔冲塞型穿孔第二阶段剪切冲塞耗能．由两阶段总的耗能最小确定第一阶段的侵彻深度,从而得到最小穿透能量的解析解．与铝合金和装甲钢靶板弹道试验数据比较表明,该文两阶段模型的计算结果与试验结果吻合较好。