金属薄靶板冲塞破坏最小穿透能量分析

基于大量弹道极限试验分析和高应变率下材料的简化热塑性本构关系,提出一种计算塑性金属靶板在刚性平头弹亚弹速冲击下冲塞剪切耗能的简化模型,建立了刚性平头弹穿透靶板所需最小能量(最小穿透能量)的无量纲表达式,得到一个计算低碳钢靶板最小穿透能量的半理论半经验公式。介绍并分析讨论了现有金属靶板最小穿透能量经验公式,得到一些有意义的结论。经分析比较,表明本文公式适用性较广、精度较好。     

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。     

陶瓷金属复合靶板工程模型及耗能分析

基于实验和数值模拟,将穿甲子弹侵彻陶瓷金属复合靶板的过程分为两个阶段,分别计算弹体侵彻陶瓷面板的动能损失、粘结层及金属背板的耗能,建立了计算弹道极限的工程分析模型,其结果与实验吻合较好。基于所建立的工程模型,分析了复合靶板各组分对其抗弹性能的影响。结果表明,陶瓷/金属复合靶板的耗能机制主要是背板耗能和弹丸质量损失耗能,分别约占初始动能的60%―95%和5%―40%。     

GCr15弹丸冲击不同厚度GH4169板的变形与破坏模式试验研究EI北大核心CSCD

为理解航空发动机包容机匣用镍基高温合金GH4169遭受高速冲击载荷时的动态力学特性,采用GCr15硬质合金弹丸,利用一级空气炮试验装置对不同厚度(2 mm、3 mm、5 mm、6 mm)的GH4169靶板进行了弹丸速度从96.7~314.2 m/s的弹道冲击试验,对冲击载荷作用下靶板的变形、破坏模式和失效机理进行了系统的试验研究。结果表明:在试验冲击速度范围之内,随着靶板厚度的增加,靶板的变形模式逐渐由拉伸与弯曲主导的蝶形变形转变为局部的剪切变形;同时靶板的破坏模式由花瓣形损伤与冲塞共存模式向单一剪切冲塞模式转变;随着冲击速度的增加,靶板对弹丸动能的吸收能量是逐渐增加的,但在临界穿透速度时出现一个拐点,使得靶板被击穿后吸收能能量的增速变缓,表明靶板被穿透破坏后降低其的吸能能力;当冲击速度为临界穿透速度时靶板变形挠度达到最大值;冲击后靶板的花瓣裂纹数量与弹体速度呈线性关系。当入射速度为284 m/s时,与试验结果比较,修正后R-I公式预测弹丸剩余速度比未修正的结果精度提高7.01%。     

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。     

卵形弹丸撞击下 FRP层合板的侵彻和穿透

研究了卵形弹丸撞击下FRP层合板的侵彻和穿透性能, 在局部化破坏模式假定的基础上改进了Wen提出的能量简化分析模型。改进模型仍假设弹体在侵彻过程中表面所受靶体的平均压力由靶体材料弹塑性变形所引起的静态阻力和速度效应引起的动阻力两部分组成, 认为侵彻过程中靶体对弹的阻力不再是一个常数, 而是与侵彻速度相关的函数。同时针对不同厚度靶板的破坏模式, 建立了几种不同的侵彻和穿透模型。通过弹头长度与靶板厚度的比较, 将侵彻过程分为部分侵彻和完全侵彻; 穿透过程分为薄板穿透和中厚板穿透。并且根据不同的破坏方式给出了求解卵形弹丸的侵彻深度、 残余速度和极限速度的预测公式。模型预测与实验数据进行了比较, 发现侵彻深度和弹道极限速度的理论预测值与实验数据吻合得很好。      

刚性尖头弹扩孔贯穿金属靶板理论模型的讨论

针对延性扩孔破坏模式,讨论了刚性尖头弹贯穿韧性金属靶板的已有六个理论模型（F-W、C-L、JZG、WHM、S-W和JBL）对于靶板厚度和弹头形状的适用范围,统一了各模型参数的选取准则,分别给出了JZG模型尖锥头形和尖卵头形弹体半锥角和无量纲曲率半径（CRH）的适用范围。基于12组冲击速度为200~1600m/s,厚径比（靶体厚度与弹身直径之比H/d）为0.605~9.17的多种弹靶材料的穿甲实验,得出：对于尖锥头形弹体贯穿靶板后的残余速度,S-W和WHM、JZG、F-W模型分别对于较薄靶板、中等厚度靶板和较厚靶板的预测效果较好;而对于尖卵头形弹体,WHM和JBL模型预测效果较好。同时,各模型对于弹道极限预测效果的结论和残余速度一致。分析结论可为坦克、舰船等单、多层金属装甲防护结构设计与计算提供参考和依据。     

TC4钛合金板厚度对其撞击失效特性影响研究

为了揭示TC4钛合金板抗撞击性能与失效模式随厚度的变化规律及机理,采用ABAQUS/Explicit有限元软件建立平头弹撞击不同厚度靶板的模型,对弹体撞击不同厚度靶板进行计算。通过对比数值仿真与撞击实验结果,验证仿真模型的有效性。研究结果表明,靶板的主要失效模式、耗能机制、弹道极限随其厚度增加会发生改变,靶板厚度存在对应的转折值。对于TC4钛合金薄板,当靶板厚度比较小时,靶板拉伸撕裂破坏占主导作用。但是,当靶板厚度比较大时,靶板主要失效模式是局部剪切破坏。当靶板厚度小于4 mm、大于8 mm时,弹道极限速度随靶板厚度的增加而增加;当厚度为4~8 mm时,弹道极速度变化不明显。     

Mg/Al波纹复合板抗冲击性能研究

目的 比对波纹轧制结构和平面复合结构的Mg/Al复合板抗冲击性能与吸能机制.方法 采用波纹辊轧制工艺制备Mg/Al复合板,使用半球形铝合金弹丸对传统平面复合板与波纹复合板进行不同速度下的冲击试验研究,并对比分析2种复合板的损伤机理,探明波纹结构对复合板抗冲击性能的影响.结果 Mg/Al平面复合板抗半球形弹丸冲击的吸能机制主要是通过靶板的塑性变形、剪切破坏、拉伸断裂、分层破坏和弹丸与靶板间摩擦等形式来吸收能量.波纹复合板对冲击能量的吸收主要依赖靶板的局部塑性变形、沿着波纹方向的开裂、结合界面的分层以及弹丸与靶板间的摩擦耗能.结论 当冲击速度低于弹道极限速度时,波纹复合板的抗冲击性能优于平面复合板,高于弹道极限速度时,2种复合板的抗冲击性能和耗能程度相当.     

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.     

Comparative analysis of perforation models of metallic plates by rigid sharp-nosed projectiles

Based on the mode of ductile hole enlargement, the present paper compares the models of a rigid sharp-nosed projectile perforating the ductile metallic target plate, given by Chen and Li [1] and Forrestal and Warren [2], respectively. It indicates that the formulae of ballistic limit and residual velocity of these two perforation models are consistent in form but with different applicable range, which due to them employing the spherical cavity expansion theory and cylindrical cavity expansion theory, alternately. Further analyses are conducted to discuss the effects of target material and plate thickness on the terminal ballistic performance with referring the experimental results of aluminum alloy and Weldox E steel plates. It is confirmed that the perforation mechanisms may transform with increasing the plate thickness and the strength of target material.     

Impact response of sandwich plates with a pyramidal lattice core

The ballistic performance edge clamped 304 stainless-steel sandwich panels has been measured by impacting the plates at mid-span with a spherical steel projectile whose impact velocity ranged from 250 to 1300 m s⁻¹. The sandwich plates comprised two identical face sheets and a pyramidal truss core: the diameter of the impacting spherical projectile was approximately half the 25 mm truss core cell size. The ballistic behavior has been compared with monolithic 304 stainless-steel plates of approximately equal areal mass and with high-strength aluminum alloy (6061-T6) sandwich panels of identical geometry. The ballistic performance is quantified in terms of the entry and exit projectile velocities while high-speed photography is used to investigate the dynamic deformation and failure mechanisms. The stainless-steel sandwich panels were found to have a much higher ballistic resistance than the 6061-T6 aluminum alloy panels on a per volume basis but the ballistic energy absorption of the aluminum structures was slightly higher on a per unit mass basis. The ballistic performance of the monolithic and sandwich panels is almost identical though the failure mechanics of these two types of structures are rather different. At high impact velocities, the monolithic plates fail by ductile hole enlargement. By contrast, only the proximal face sheet of the sandwich plate undergoes this type of failure. The distal face sheet fails by a petalling mode over the entire velocity range investigated here. Given the substantially higher blast resistance of sandwich plates compared to monolithic plates of equal mass, we conclude that sandwich plates display a potential to outperform monolithic plates in multi-functional applications that combine blast resistance and ballistic performance.     

Perforation of a thick plate by rigid projectiles

Perforation of a thick plate by rigid projectiles with various geometrical characteristics is studied in the present paper. The rigid projectile is subjected to the resistant force from the surrounding medium, which is formulated by the dynamic cavity expansion theory. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose, are considered in the proposed analytical model. Simple and explicit formulae are obtained to predict the ballistic limit and residual velocity for the perforation of thick metallic plates, which agree with available experimental results with satisfactory accuracy.     

An analytical model for tumbling projectile perforation of thin aluminum plates

An analytical model for the perforation of thin aluminum targets by tumbling cylindrical projectiles was developed. The target material was considered to be rigid—perfectly plastic without strain hardening, while the projectile was treated as undeformable. The perforation process was experimentally found to consist of three stages: plugging, hole enlargement, and front petaling. Both conservation of energy and conservation of momentum laws were used for modeling the plugging stage, while a lower bound method was employed during the hole enlargement stage. The energy dissipated during the petaling stage consists of shearing fracture of the petal, localized plastic shear in a zone contiguous with the edges, the momentum of the petal and the bending energy of the petal. The analytical results provided generally good agreement with the corresponding experimental data in terms of the final velocity and final oblique angle of the projectile as well as the crater length of the target.     

Fundamental solutions of cavitation in porous solids: a comparative study

The expansion of internally pressurized cavities, embedded in infinite bodies, in spherical and cylindrical (plane strain and plane stress) configurations, is investigated within the framework of finite plasticity. Material response is modeled by the Gurson theory for porous solids and includes strain hardening. Numerical results, obtained under the assumption of nearly universal loading histories, reveal limit cavitation states for all three deformation patterns. Cavitation is identified with asymptotic levels of the specific cavitation energy, which is highest for the spherical cavity and smallest for plane stress (plate) holes. The influence of material porosity is assessed in context of weight optimization of protective plates. A limited comparison with experimental data for porous titanium plate perforation reveals close prediction of ballistic limit velocity.     

An engineering model to predict perforation damage to plates impacted by high velocity debris clouds

This paper describes experiments and the development of a model to predict damage to metallic plates impacted by high velocity, multi-particle debris clouds. The experiments involved single steel spheres fired at a steel shatter plate at speeds near 1.5 and 2.0 km/sec to generate the debris clouds. In each series of tests, the impact velocity was controlled, and a witness plate was placed at increasing distances behind the shatter plate to observe the effects of debris particle dispersion on plate damage. This paper focuses on the variations, with plate spacing, in the size of the central region removed from the witness plates. The central hole size model compares the post impact kinetic energy distribution in a witness plate impacted by a debris cloud to the free impact residual kinetic energy in an equivalent plate impacted by an L/D=1 steel cylinder, at the ballistic limit velocity. This approach permits extension of the model to other plate materials through utilization of existing ballistic limit velocity data.     

Influence of surface coating on ballistic performance of aluminum plates subjected to high velocity impact loads

Ballistic response of single or multi-layered metal armor systems subjected to high velocity impact loads was investigated in many experimental, theoretical and numerical studies. In this study, influences of plasma spray surface coating on high velocity impact resistance of AA 6061 T651 aluminum plates were analyzed experimentally. Two different types of surface coating were applied to plates using plasma spray. Using 9.00 mm Parabellum bullets, ballistic performance of both uncoated and coated plates was tested. After the impact tests, penetration depth including plate bending on the front face and bulging on the rear face of the target plate was measured. The improvement on the ballistic resistance of the coated plates was clearly observed. The increase in non-perforating projectile velocity and the decrease in penetration depth were both experienced.     

SiC和B4C防弹插板抗多发弹打击损伤特性研

使用87式5.8 mm钢芯弹分别对SiC和B₄C复合防弹插板进行实弹靶试试验, 通过对鉴证靶凹陷深度、防弹插板背凸体积和X射线数字直接成像检测系统(DR)对防弹插板弹击损伤情况进行分析, 同时结合陶瓷材料显微结构和力学性能分析对防弹插板抗多发弹打击损伤特性进行了研究。结果表明, SiC和B₄C防弹插板都能有效防御3发5.8 mm钢芯弹的连续打击, 具有较好的抗多发弹打击性能;B₄C防弹插板与SiC防弹插板受弹击后鉴证靶凹陷深度相当, 其背凸体积较SiC防弹插板降低超过35%, 陶瓷锥底面平均直径增加30%以上, 吸收了更多的弹丸冲击动能, 这与B₄C陶瓷具有较高的硬度有关。     

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。