弹体高速侵彻陶瓷复合厚靶的计算模型研究

针对平头弹高速撞击陶瓷复合厚靶的问题,以集中质量法为基础并考虑靶体的内摩擦效应对Fellows模型加以改进,建立侵彻过程的理论计算模型并利用Matlab编程求得不同撞击速度下弹体侵彻复合靶体的侵彻深度,模型得到了试验结果和数值计算结果的验证。参数分析的结果表明,陶瓷厚度的增加可提高复合靶体的抗侵彻能力,但随着初始撞击速度的提高,弹体的侵彻深度增长曲线趋于平缓。     

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。     

圆柱形长杆超高速正碰撞薄板结构破碎效应

超高速碰撞多层板结构破碎效应研究对空间碎片防护及动能武器毁伤效应研究有着重要意义。采用ANSYS/AUTODYN程序的SPH方法,对超高速碰撞碎片云的形成过程进行了数值模拟,某典型时刻一次及二次碎片云形貌的数值模拟结果与实验结果吻合较好,验证了计算方法和模型参数的正确性。在此基础上采用数值模拟方法,对钨合金、轧制均质装甲(Rolled Homogeneous Armor,RHA)及LY12铝三种材料的圆柱形弹体超高速碰撞薄板的破碎规律进行了研究,基于量纲分析方法得出了弹体破碎长度随弹靶材料特性、弹靶尺寸及初始撞击速度变化的关系式。并研究了钨合金及RHA两种材料的长杆弹对八层RHA板结构的超高速碰撞效应。     

陶瓷-活性粉末混凝土复合靶抗侵彻试验研究

为研究陶瓷材料应用到工程防护领域的抗侵彻性能。设计了3块陶瓷-活性粉末混凝土复合靶,利用直径125 mm的特制弹体对陶瓷-活性混凝土复合靶体进行DOP(Depth of Penetration)侵彻试验,得到了弹体的飞行姿态、着靶速度、破坏形态和靶体的侵彻深度、弹坑范围、破坏形态等试验参数,定性分析了陶瓷靶厚度和纤维层约束作用对复合靶体抗侵彻性能的影响;结果表明:陶瓷靶具有优良的抗侵彻性能,在低速(360～400 m/s)情况下对弹体能产生一定侵蚀作用;随着陶瓷靶厚度的增加,陶瓷靶的破坏形态由冲切贯穿型转变为变形凸起型破坏,耗能能力增加,复合靶体的整体抗侵彻能力增强;采用修正的别列赞公式对陶瓷靶的侵彻系数进行了初步分析,并计算了三种厚度陶瓷靶的质量防护系数和差分防护系数。结果表明,试验所用陶瓷靶的抗侵彻能力约为普通C40混凝土的4.9倍,从而为陶瓷材料在重要防护工程的推广使用提供参考。     

高速长杆弹对有限直径金属厚靶的侵彻分析EI北大核心CSCD

采用基于统一强度理论的有限柱形空腔膨胀理论,结合Tate磨蚀杆模型,考虑中间主应力、靶体侧面自由边界的影响及高速(1500 m/s~2200 m/s)侵彻弹体的变形和消蚀现象,推导线性硬化有限直径金属厚靶在长杆弹高速侵彻时的空腔壁径向应力,建立侵彻阻力和侵彻深度计算模型,并利用MATLAB软件编程求解,分析包括强度准则差异在内的弹道终点效应的一系列影响因素。结果表明:该文计算方法可以更好地描述弹靶的动态响应,还可以得到一系列基于不同强度准则的侵彻阻力和深度的解析解、对不同靶弹半径比的靶材侵彻深度的区间范围进行有效预测;强度参数、弹体撞击速度和靶体半径对有限直径金属靶体的抗侵彻性能均有较大的影响,其中强度参数值由1减小为0时,侵彻阻力可减小33.33%,侵彻深度可增加15.93%;当靶弹半径比小于等于20时,侵彻深度增大的程度显著,当靶弹半径比由19.88减小至4.9时,侵彻阻力减小了41.30%,侵彻深度增长了32.61%,此时靶体边界尺寸对侵彻性能的影响很大,不能继续按照半无限靶体进行计算。     

有限柱形空腔膨胀理论及其应用

为研究有限平面尺寸金属厚靶侵彻问题,提出了有限柱形空腔膨胀理论.考虑侧面自由边界,将理想弹塑性材料的空腔膨胀过程分为弹塑性阶段和塑性阶段,得到了空腔壁径向压力的解析解.基于Tate磨蚀杆模型,应用有限柱形空腔膨胀理论计算靶的侵彻阻力,建立了长杆弹侵彻有限直径圆柱形金属厚靶工程模型.与现有文献试验比较表明,文中工程模型计算的侵彻深度与弹道试验结果吻合较好.     

中低速长杆弹侵彻半无限岩石靶的动态响应研究

该文将统一强度理论与岩石材料动力强度依赖应变率效应的物理模型相结合,建立了岩石材料在侵彻等动力荷载作用下的率型动态统一强度准则。基于修正的土盘浮动锁应变模型,考虑应变率效应、中间主应力效应、强度准则差异和弹头滑动摩擦的影响,推导了土盘整体平均锁应力和整体平均锁应变的表达式。采用MATLAB数值计算软件和四阶Runge-Kutta算法编制计算程序,求解了中低速（V ≤ 900 m/s）长杆弹侵彻条件下弹体的侵彻深度,研究了侵彻过程中弹体的运动规律及靶体的动态响应,分析了各参数对弹体侵深的影响特性。研究表明:该文计算方法可以较好地描述整个侵彻过程中弹、靶的动态响应,还可以得到一系列基于不同强度准则的侵彻深度的解析解,有效地预测弹体侵深的上限值和下限值;中间主应力效应、强度准则差异和弹头滑动摩擦对岩石靶的抗侵彻性能具有重要影响。     

爆炸产生破片对陶瓷/纤维复合靶板的侵彻分析

采用Ansys/LS-DYNA程序,对平头柱形破片以706 m/s速度正入射陶瓷/纤维复合靶板的侵彻过程进行分析,得出了复合靶板的防护能力与陶瓷层、纤维层厚度的变化规律.通过弹靶撞击实验和模拟曲线分析.进一步优化了复合靶板的结构参数.     

“上帝之杖”天基动能武器毁伤效应评估

作为未来化战争条件下打击地下深层战略目标的一种重要武器装备,“上帝之杖”天基动能武器对维护国家利益和领土完整意义重大。综合考虑了外界温度、压强、海拔高度、大气密度、飞行速度等因素对弹体在大气层中所受空气阻力的影响,分析计算出“上帝之杖”动能弹的入地速度达3 401.7 m/s;目前,受到实验技术和方法的限制,只有Gold取得了几组动能弹高速侵彻混凝土靶的实验数据,且最高侵彻速度不足2 km/s,对诸如“上帝之杖”这么高侵彻速度的动能弹侵彻混凝土靶的实验研究还是空白;因此,进行了“上帝之杖”动能弹侵彻C60半无限混凝土靶的数值模拟和理论研究。研究结果表明:数值模拟所得的最终侵彻深度(18.9 m)与理论计算结果(17.3 m)的误差在允许的范围内,混凝土靶的最终开坑直径达7.333倍弹径;不同于刚性弹侵彻过程中侵彻速度持续衰减的特点,“上帝之杖”超高速动能弹侵彻的瞬态高压阶段弹头侵彻速度锐减,动能损失率极高,相应侵彻深度小;稳定侵彻阶段弹头侵彻速度和弹长消蚀速度保持稳定,弹体动能损失率基本不变,侵彻深度却线性增加;当动能弹着靶速度足够大时,最终侵彻深度主要受弹靶材料密度控制,受弹靶强度影响不大,高密度分层防护结构在抗超高速动能弹侵彻领域优势显著。     

陶瓷/金属复合靶抗侵彻性能的数值模拟方法研究

采用自主开发的欧拉型二维爆炸与冲击问题仿真软件EXPLOSION-2D对钨杆侵彻陶瓷/金属复合靶板进行了数值模拟研究。为了描述陶瓷材料的损伤特性,在软件中嵌入JH-2本构模型及通过平板撞击实验结果拟合得到的高压状态方程。在质点网格法的基础上,给出了在欧拉算法下脆性材料累积损伤、破坏的数值算法。采用上述模型及算法研究了不同陶瓷片厚度条件下陶瓷/金属复合靶板的抗侵彻性能,分析了陶瓷靶损伤演化规律和侵彻过程。数值模拟结果与DOP(侵彻深度实验)结果吻合得较好,验证了该文模型和算法的有效性。     

The response of layered aluminum nitride targets subjected to hypervelocity impact

This work presents both experimental and computational ballistic results of layered Aluminum Nitride (AlN) targets. An L/D = 6 tungsten penetrator is used to impact AlN targets at a nominal impact velocity of 2100m/s. The primary objective of this work is to determine the ballistic performance of layered ceramic targets to hypervelocity impact. Various layering configurations are investigated including separating the AlN ceramic layers by thin, low impedance, polymethyl methacrylate (PMMA). PMMA thicknesses of 1 mm, 0.5 mm and 0 mm are used. The number of AlN ceramic layers is also investigated. Target configurations of two, four, six, and twelve layers are considered. All targets consist of 76.2 mm of AlN. The experiments show that target resistance decreases when PMMA is added. Target resistance is also reduced when more layers are used. A secondary objective of this work is to evaluate the ballistic effect of reducing the lateral dimension of the ceramic tile (reduction in self-confinement). The experiments show reduced target resistance when the lateral tile size is decreased. Computations of selected experiments are presented to provide insight into the behavior of the AlN targets. The computations capture the effect of layering, PMMA separation and lateral tile size and provide insight into the behavior of the ceramic when used in these types of configurations.     

An investigation on mass loss of ogival projectiles penetrating concrete targets

Mass loss of an ogival projectile during its normal penetration in concrete target was investigated in this paper. Experiments of 38CrSi short-rod projectiles with ogival nose shape penetrating into concrete targets were conducted in the striking velocity range of 500–1500 m/s. Discussions revealed that projectile mass loss derives mainly from the nose part for both short-rod and long-rod projectiles during the penetration process. Furthermore, an engineering model was proposed to determine upper limit of rigid penetration regime as the maximum value of the striking velocity, which was based on the feature of projectile mass loss in the hydrodynamic transition between rigid penetration regime and semi-hydrodynamic penetration regime. Good agreements are obtained between engineering predictions and experimental results.     

A generalized formula for the penetration depth of a deformable projectile

A simple analytical algebraic formula is developed for predicting the penetration depth of a deformable projectile into a semi-infinite target. This formula is a simplified version of more general equations that have been developed to predict the time-dependent penetration process in finite thickness targets. Specifically, the formula generalizes the classical hydrodynamic theory to include dependence on elastic properties of the target and on the yield strengths of both the target and the projectile. Moreover, the formula is limited to the case of long-rod penetration where both the projectile and the target experience significant plastic flow. The limiting values of the location of the elastic–plastic boundary in the target have been determined, and a single empirical constant has been introduced to characterize the transition between these limiting values. A value for this empirical constant has been determined which produces theoretical predictions that are in reasonable agreement with experimental data for moderate to high values of the impact velocity of steel and tungsten projectiles penetrating a steel target.     

基于FE-SPH自适应耦合算法对长杆弹侵彻反应装甲的模拟研究

该文采用自编程序实现的FE-SPH 自适应耦合算法对长杆弹侵彻反应装甲的过程开展了数值模拟研究。为了实现反应装甲中的凝聚炸药在长杆弹冲击作用下的起爆过程,在FE-SPH 自适应耦合算法中嵌入了凝聚炸药的点火-增长模型。该文首先应用FE-SPH 自适应耦合算法对二维轴对称反应装甲冲击起爆模型进行了模拟分析,并以此验证了自适应FE-SPH 自适应耦合算法对此类问题模拟的可行性和有效性。其次,针对长杆弹斜侵彻反应装甲的过程进行模拟,再现了反应装甲动态响应干扰长杆弹入侵的过程。通过与相关实验数据结果及其他方法模拟的结果对比,FE-SPH 自适应耦合方法能够有效地对长杆弹侵彻反应装甲和后效目标靶进行一体化仿真。     

Penetration erosion phenomenology

Penetration experiments of one-third scale tungsten alloy projectiles, with aspect ratios of 15 and 30 were performed in armor-like steel targets for impact velocities between 0.8 and 1.8 km/s. Post-test flash radiographs show that portions of the penetration channel are filled with the erosion products from the projectile. The erosion phenomenology of long-rod tungsten alloy penetrators was deduced by sectioning penetration channels and examining metallographic sections.     

Deformation and fracture of a long-rod projectile induced by an oblique moving plate: Experimental tests

The influence of projectile length to diameter ratio (15, 30 and 45), plate thickness (0.5, 1 and 2 projectile diameters), projectile velocity (1500, 2000 and 2500 m/s) and plate velocity (−300 to 300 m/s) on the interaction between long-rod tungsten projectiles and oblique steel plates (obliquity 60°) was studied experimentally in small-scale reverse impact tests. The residual projectiles and their motions were characterised in terms of changes in length, velocity, angular momentum, linear momentum and kinetic energy. The parameters found to have the largest influence on the disturbance of the projectile were the plate velocity, in particular its direction, and the thickness of the plate. In the ranges studied, the influence of length to diameter ratio and of projectile velocity were found to be less important.     

Influence of scale on the penetration of tungsten rods into steel-backed alumina targets

As ballistic tests are often performed in reduced geometrical scale, the scaling laws are important for the interpretation of the results. In this study, we tested the validity of replica scaling, by which we mean that all geometrical dimensions are scaled uniformly, while the materials and the impact velocity are kept the same. Long tungsten projectiles with length-to-diameter ratio 15 were fired against unconfined alumina targets with steel backing. The tests were carried out with impact velocities 1500 m s⁻¹ and 2500 m s⁻¹, and in three different scales with projectile lengths 30, 75 and 150 mm (diameters 2, 5 and 10 mm). The alumina targets were photographed by means of a high-speed camera, and the tungsten projectiles were photographed inside the alumina targets by means of flash radiography. Also, the residual penetrations in the steel backings were measured. The Johnson-Holmquist model for ceramic materials was implemented into the AUTODYN code, which was used for simulation of the experiments. The agreement between results of experiment and simulation was fair, and over the tested interval of scales replica scaling was found to be valid with reasonable accuracy.     

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。     

The relation between ballastic efficiency and compressive strength of ceramic tiles

Ballistic tests with armor piercing projectiles on different ceramic tiles are presented. The tests were conducted using the thick-backing configuration, which is a new experimental technique to evaluate ballistic efficiencies of ceramic tiles. The residual penetration of the projectile into a thick metallic backing plate, which supports the ceramic tile, is measured. It is shown that the ballistic efficiencies of the different tiles increase monotonically with their normalized effective strength. This strength parameter is defined as the average of the static and dynamic compressive strengths divided by the density of the ceramic. A simple analysis is presented which accounts for the linear dependence of the ballistic efficiency on the normalized effective strength.     

A new analytical model of normal penetration of projectiles into the light-weight ceramic–metal targets

In this paper based on Zaera and Sanchez-Galvez [4] model, a new analytical model has been presented for penetration of deformable projectiles into ceramic–metal targets. By considering erosion and flattening of projectile tip, the one-dimensional equation of motion has been established. The momentum equation has been employed to describe the fragmented ceramic conoid. Considering work hardening material behavior, energy conservation equation has also been used for modeling the deformation of back-up metallic plate. Semi-angle of ceramic conoid is modified based on Wilson and Hetherington [8] experiments. The ballistic limit and residual velocity of projectile predicted by new analytical model have a good agreement with the experimental results.