高速钝头弹侵彻中厚金属靶板的机理研究

根据侵彻过程中的不同受力状态,将高速钝头弹对中厚金属靶板的侵彻过程划分为简单压缩阶段、压缩剪切阶段和绝热剪切阶段,每个侵彻阶段都呈现出不同的吸能模式。基于三阶段侵彻机理,建立了钝头弹侵彻中厚金属靶板的弹道极限和剩余速度计算模型;利用侵彻模型计算了3.3g立方体和9.7g圆柱体侵彻4mm、6mm和10mm船用钢的剩余速度,计算值与试验值有较好的吻合。三阶段侵彻模型考虑了试验中出现的发热、发光等现象的吸能,并对金属靶板的抗弹能力和钝头弹的侵彻能力进行了预测,可以降低试验成本,具有一定的理论价值和工程应用价值。     

高速钝头弹侵彻中厚高强聚乙烯纤维增强塑料层合板的机制

根据侵彻过程中的不同受力状态和耗能机制,结合高强聚乙烯纤维增强塑料(UFRP)层合板抗高速侵彻特点,将高速钝头弹对中厚UFRP的侵彻过程分为压缩镦粗、剪切压缩和拉伸变形三个阶段。基于三阶段侵彻机制,利用能量守恒原理建立了钝头弹高速侵彻中厚UFRP的弹道极限和剩余速度计算模型。采用侵彻模型计算了相关文献弹道试验工况下弹体的剩余速度和弹道极限速度,计算值与文献试验值吻合较好。三阶段侵彻模型考虑了试验中出现的纤维熔断和弹体镦粗现象,能够对高速钝头弹侵彻中厚UFRP的剩余速度和弹道极限速度进行合理预测,具有一定的理论价值和工程应用价值。     

刚性钝头弹体正贯穿中厚金属靶的挤凿块速度模型

从挤凿破坏机理出发,考虑了能量守恒定律和剪切冲塞模型,提出了适用于刚性钝头弹体(平头、半球形头、球形)正贯穿中厚金属靶的挤凿块速度模型。设计了穿甲实验,以直径8 mm钨球正冲击3 mm厚GH4169靶板,得到了球形弹体相应的挤凿块数据,结合文献中平头和半球形头弹体实验数据验证了挤凿块速度模型的适用性,模型计算结果与实验数据一致性良好。提出的挤凿块速度模型可用于计算挤凿块对靶后目标的毁伤能力。     

破片模拟弹侵彻钢板的有限元分析

根据破片模拟弹侵彻钢板的实验研究，采用MSC．Dytran对破片模拟弹侵彻钢板的侵彻过程、侵彻特性、钢板的破坏模式以及弹体的侵彻速度、靶板的侵彻阻力进行了有限元分析，并将分析结果与实验结果进行了比较．分析结果表明，破片模拟弹冲击钢装甲的侵彻过程可大致分为初始接触、弹体侵入、剪切冲塞和穿甲破坏4个阶段．有限元分析的破片模拟弹侵彻特性及靶板破坏模式与实验观测结果有较好的一致性，在靶板破口的正面，与弹体平面凸缘两端接触的部分，变形以剪切为主，而与切削面接触的部分，以挤压变形为主；靶板破口背面为剪切冲塞破坏；有限元模拟的弹体剩余速度与实验结果吻合较好，弹体侵彻过程中弹靶作用界面的速度和侵彻速度近似呈线性变化．有限元分析结果还表明，采用适当的模型，有限元法能较好地模拟破片模拟弹侵彻钢板的侵彻过程、侵彻特性以及钢板的破坏模式．     

尖头弹侵彻延性金属靶板弹道极限的解析模型

现有的尖头弹侵彻金属靶板的弹道极限计算模型往往需要大量的试验数据和靶板材料的动态性能参数,且没有考虑侵彻速度对侵彻效果的影响,这给工程应用带来了很大的不便和误差。基于这一问题,考虑速度效应和靶板材料参数对侵彻的影响,结合流体动力学原理与动态空穴膨胀理论,分别提出了双模式和单模式侵彻模型。双模式侵彻模型的侵彻过程可分为两个阶段：流体动力变形阶段和塑性变形阶段,当侵彻速度小于靶材产生流体动力变形的临界速度时,侵彻进入塑性变形阶段,根据功能原理,建立了计算弹道极限的解析模型;单模式侵彻模型仅考虑塑性变形阶段。解析模型计算的弹道极限与弹道试验结果吻合的较好,且模型中不涉及弹道试验数据和靶板材料的动态性能参数,易于迅速求解,便于工程应用,可用于对延性金属靶板抗尖头弹侵彻能力的评估。     

长管体斜侵彻半无限均质靶简化模型

长管体斜侵彻半无限靶的研究具有重要意义。描述了长管体在速度范围在1000m/s~1500m/s时斜侵彻半无限均质靶板的物理图像,对长管体在侵彻各个阶段的受力和运动情况进行了分析,发现侵彻时管体中央的“靶芯”对侵彻过程影响很大。在一定假设条件下,基于变质量系统动量守恒定律建立了不同侵彻阶段长管体侵彻的质心运动方程,基于动量矩定理建立了不同侵彻阶段绕质心的摆动方程,并进行了数值计算。进行了长管体侵彻半无限均质靶板的试验,试验与计算结果表明二者的侵彻行程吻合较好,说明所建立的模型能够描述长管体对半无限均质靶板的侵彻过程,对空心弹和异形穿甲弹的研究和设计具有一定参考价值。     

长杆弹超高速侵彻半无限靶理论模型的对比分析与讨论

分别基于六组典型长杆弹超高速侵彻金属靶体以及三组长杆弹侵蚀侵彻混凝土靶体的实验数据,对经典一维AT模型及其五个改进模型对弹体侵彻深度的预测能力进行了评估,并讨论了靶体等效强度(Rt)变化以及弹体的轴线速度变化。计算结果表明,对于长杆弹高速侵彻金属靶体的分析计算,应首选AW模型,其次为LW模型。而对于混凝土靶体,已有有限的实验数据表明,上述六个模型对于长杆弹侵蚀侵彻混凝土靶体侵彻深度预测均不适用,其主要原因在于Rt不能反映超高速侵彻下混凝土靶体的响应。最后基于分析结果,给出了长杆弹侵蚀侵彻混凝土靶体进一步的研究方向。     

基于加速度测试及模糊模型的弹丸侵彻混凝土深度实时预测方法

为了对卵形弹垂直侵彻半无限厚混凝土目标的侵深进行实时预测,提出了一种基于实测加速度值及模糊模型的计算方法。该方法根据瞬时速度的不同将侵彻过程分成了高速侵彻、中速侵彻和低速侵彻三个阶段,并分别采用不同的模型对每个阶段的减加速度、速度和侵彻深度进行了描述。通过判断减加速度的计算误差,自动确定了高速侵彻阶段与中速侵彻阶段以及中速侵彻阶段与低速侵彻阶段的截点速度。同时,利用实测的全弹道加速度曲线,实时计算了侵彻过程的初始冲击速度。将实验后所测得的侵彻深度与模型预测的侵彻深度进行比较,结果表明该预测方法可以对侵彻深度进行准确地实时计算。     

破片着靶点位置对拼接的UHMWPE板抗侵彻性能影响数值研究

UHMWPE板抗侵彻性能优异但在实际使用过程中需切割成一定尺寸后再拼接安装,半穿甲导弹内爆后形成的高速破片侵彻UHMWPE板时弹着点位置具有随机性。利用数值仿真方法研究破片着靶点位置、破片速度、破片长径比对拼接的UHMWPE板抗侵彻性能的影响。结果表明:破片开始侵彻UHMWPE板时,UHMWPE板在弯矩和剪应力共同作用下出现纤维剪切破坏;随着破片继续侵彻,UHMWPE板主要受到弯矩作用发生纤维拉伸断裂破坏并伴随有严重的分层现象;当破片侵彻两块拼接的UHMWPE板速度较低(小于1 000 m/s)时,拼接的UHMWPE板存在明显的抗弹薄弱区,薄弱区域的范围大约为3倍的弹径;当破片侵彻四块拼接板时,可将靶板划分为薄弱,次薄弱及正常区域。考虑到半穿甲导弹产生破片的大小和安装工艺的方便性,认为UHMWPE板拼接安装时,拼接缝两侧10 cm范围内作为抗弹薄弱区域,需要加固。     

侵彻单层靶时着靶姿态对装药损伤的影响规律研究

为研究着靶姿态对高速侵彻弹装药损伤的影响,依据实际战斗部的结构尺寸设计了小尺寸模型试验弹,在125 mm口径的滑膛炮发射平台上开展了试验弹以不同攻角斜侵彻单层钢靶试验。通过理论计算得到着靶姿态对侵彻过程能量损失的影响。利用CT扫描无损检测技术观测不同着靶姿态下试验弹内部的损伤情况。运用LS-DYNA对试验弹侵彻钢靶过程中装药的力学响应过程进行模拟计算。结果表明:在斜侵彻单层钢靶的过程中,着角一定时,能量损耗与攻角呈指数关系;试验弹的倾角越大,装药尾部受到的应力波拉伸压缩反复作用越明显,装药在侵彻过程中长度变化越大,更易出现深度裂纹、塌边等损伤;壳体外形变化会引起装药受到的压缩应力阻碍微裂纹的扩展和滑移,减少宏观损伤的出现。     

The ballistic performance of metal plates subjected to impact by projectiles of different strength

In this paper, the ballistic performance of monolithic, double- and three-layered steel plates impacted by projectiles of different strength is experimentally investigated by a gas gun. The ballistic limit velocity for each configuration target is obtained and compared based on the investigation of the effect of the number of layers and the strength of projectiles on the ballistic resistance. The results showed that monolithic plates had higher ballistic limit velocities than multi-layered plates for projectiles of low strength regardless their nose shape, and also the ballistic limit velocities of plates decreased with the increase of the number of layers. Moreover, monolithic plates showed greater ballistic limit velocities than multi-layered plates for ogival-nosed projectiles of high strength, and also the ballistic limit velocities of plates decreased with the increase of the number of layers. However, monolithic plates had lower ballistic limit velocities than multi-layered plates for blunt-nosed projectiles of high strength, and also the ballistic limit velocities of plates increased with the increase of the number of layers. The differences in the ballistic limit velocities between various impact conditions can be related to the transitions of perforation mechanisms and failure models of plates and projectiles.     

Ballistic penetration of steel plates

This paper presents a research programme in progress where the main objective is to study the behaviour of Weldox 460 E steel plates impacted by blunt-nosed cylindrical projectiles in the lower ordnance velocity regime. A compressed gas gun is used to carry out high-precision tests, and a digital high-speed camera system is used to photograph the penetration process. A coupled constitutive model of viscoplasticity and ductile damage is formulated and implemented into the non-linear finite element code LS-DYNA, and the material constants for the target plate are determined. The proposed model is applied in simulations of the plate penetration problem and the results are compared with test data. Good agreement between the numerical simulations and the experimental results is found for velocities well above the ballistic limit, while the ballistic limit itself is overestimated by approximately 10% in the numerical simulations.     

A numerical comparison of the ballistic performance of unitary rod and segmented-rods against stationary and moving oblique plates

The purpose of this paper is to investigate the ballistic performance of segmented-rods against stationary or moving oblique plates. To do this, a series of three-dimensional numerical simulations for the impact characteristics of segmented-rods (5 of L/D=1) into stationary or moving oblique thin-plate targets is conduced. To provide a base line data, an L/D=5 unitary rod projectile which has the same mass and kinetic energy is also considered. The ballistic characteristics of the projectiles are evaluated by examining the crater profile in a thick witness target that is placed behind the oblique plate. The impact velocities considered are 1400, 1800 and 2200 m/s. The results for the test range show that the unitary rod projectile shows better performance in the moving oblique target than the stationary one and the segmented-rods always show slightly better performance in the stationary target. From the impact velocity of 2200 m/s, the outstanding penetration performance of the segmented-rods can be observed. This trend is due to the interaction between the reactive plate and projectile. The extent of the interaction relies on the relative velocities of the plate and projectiles, the plate angle and extended total length of the segmented-rods     

Q235钢单层板对平头刚性弹抗穿甲特性研究

采用撞击实验和理论模型对单层金属板的抗侵彻性能进行了研究,分析了靶体厚度对抗侵彻性能的影响。通过对比撞击实验和理论模型计算结果,验证了理论模型和参数的有效性。结果表明,采用合适的理论模型能够有效地预测靶板在弹体撞击下的弹道极限。此外,分析了靶体在弹体撞击下的塑性变形总耗能,包括靶板局部变形和整体变形的耗能,同时考虑了靶体材料的应变率效应。在平头弹撞击厚靶的工况中,引入了一个修正函数对靶体厚度进行修正。     

Impact of thick PMMA plates by long projectiles at low velocities. Part I: Effect of head’s shape

A hybrid experimental–numerical investigation of the penetration process in thick polymethylmethacrylate (PMMA) plates was carried out. The response of such plates to the impact of long hard steel projectiles having either blunt, hemispherical or ogive-head shapes was investigated experimentally in the range of velocities of 100 (m/s) < V₀ < 250 (m/s). The penetration process can be divided into 3 stages: entrance, propagation and backwards bouncing. The last two stages are associated with brittle fracture of the plates. The tests were modeled using 3D explicit finite element analyses. The numerical results provide insight regarding the variations of field variables such as stresses, velocities, resisting forces and energies. A good agreement regarding the trajectory of the projectile and the depths of penetration is obtained. The enhanced backwards bouncing phenomenon is explained, and it is shown that the average deceleration during the penetration process is constant. The resisting force to the penetration is higher for blunt projectiles. It is 10% lower for the hemispherical head and 50% lower for ogive-headed projectiles.     

弹体头部形状对碳纤维层合板抗冲击性能影响实验研究

为研究弹体头部形状对碳纤维层合板抗冲击性能的影响,利用一级气炮发射卵形头弹、半球形头弹和平头弹,对2 mm厚碳纤维层合板进行了冲击实验。利用公式拟合处理实验数据,揭示弹体头部形状对靶板弹道极限与能量吸收的影响,并且分析靶板冲击损伤形貌及机理特征。研究结果表明:平头弹弹道极限最高,半球形头弹次之,卵形头弹最低。弹体在低速度冲击时,弹体头部形状对靶板能量吸收率的影响更为显著。平头弹冲击时,靶板迎弹面受到均匀分布的环向剪切力,纤维同时被剪切,基体发生大面积剪切破坏。半球形头弹冲击时,靶板迎弹面受到非均匀分布的剪切力和挤压作用,纤维发生剪切断裂和拉伸断裂,基体发生剪切破坏和挤压破碎。卵形头弹冲击时,纤维发生单一的拉伸断裂,而基体则发生挤压破碎。弹体头部形状对靶板损伤的影响主要集中在迎弹面和中部纤维层。     

Plate perforation by deformable projectiles — A plastic wave theory

A one-dimensional wave propagation model of plate perforation is developed for cylindrical projectiles impacting plates at normal obliquity. This theory assumes that the projectile and plate materials are rigid-linearly strain-hardening and rigid-perfectly plastic respectively, with respect to engineering stress and strain. During penetration, the projectile deforms and a plug forms in the plate. The plug which is sheared from the plate is larger than the initial cross-section of the projectile. Residual velocity, plug mass and final plug thickness are determined for this model and compared with experiments on ductile metal plates impacted at velocities larger than the minimum perforation velocity.