破片斜侵彻靶板弹道极限速度分析

文中以球型破片为对象,采用实验和仿真方法研究了钨球斜侵彻不同结构靶板时,弹道极限速度随侵彻角的变化趋势.研究表明钨球斜侵彻不同结构的靶板时,弹道极限速度随侵彻角的变化规律具有相似性;同时还研究了与钨球同质量、同体积的钢球斜侵彻同一结构靶板时,弹道极限速度随侵彻角的变化趋势,得出了相应结论对于同一球型破片,直侵彻能贯穿的靶板,当侵彻角大于一定值时,即使侵彻速度很高也无法贯穿,直至破片碎裂嵌埋.上述结论,对战斗部威力设计、弹靶作用最佳位置的确定都具有十分重要的意义.     

无量纲参数对破片弹道极限速度的影响

为开展93W钨合金破片对616装甲钢侵彻性能的研究,通过弹道枪试验分别对立方破片(底面为正方形)和圆柱破片进行了弹道极限速度测试,并基于试验结果对理论公式进行了修正,修正后的公式可应用于预测破片弹道极限速度。将仿真结果与试验结果进行了对比,验证了材料的可靠性,根据破片初速及剩余速度建立回归方程,外推得到破片的弹道极限速度,并进一步研究了无量纲弹长及无量纲靶厚对弹道极限速度的影响。结果表明,当确定破片及靶板的材料后,弹道极限速度仅与无量纲弹长和无量纲靶厚有关; 当无量纲弹长与无量纲靶厚确定后,破片形状对弹道极限速度的影响非常明显,立方破片更容易穿透靶板。当无量纲靶厚为1.6时,破片正侵彻12 mm厚度的靶板,弹道极限速度随破片无量纲弹长的增加而加大,且无量纲弹长每增加0.1,破片的弹道极限速度增加约45 m/s; 当无量纲弹长为1.0时,破片正侵彻不同厚度的靶板,弹道极限速度随无量纲靶厚的增加而加大,且无量纲靶厚每增加0.1,破片的弹道极限速度增加约50 m/s。     

几种钨合金破片垂直侵彻装甲钢板极限穿透速度研究

文中从理论和实验两个方面研究了战斗部中典型的预制破片钨球、钨柱和钨块对装甲钢板的侵彻性能；分析了钨柱、钨块破片因着靶姿态不同存在着不同的极限穿透速度；给出了不同着靶姿态侵彻阻力面的理论模型，推导出了计算极限穿透速度的公式，并计算了三种典型预制破片的极限穿透速度，与测试的弹道极限进行了对比。     

一种考虑球体变形的钨球侵彻低碳钢深度计算模型

为了研究钨球在高速撞击下的变形行为对侵彻效果的影响,对钨球侵彻半无限低碳钢靶进行试验研究,得到<1 600 m/s冲击速度下钨球变形特征和靶板侵彻深度随冲击速度的变化规律。在此基础上构建钨球侵彻塑性变形模型。将钨球变形模型和球形空腔膨胀阻力模型相结合,建立钨球变形侵彻深度计算模型。对比不同撞击速度下钨球变形侵彻模型、刚性侵彻模型的计算结果。对比结果表明,变形侵彻模型能够更加准确地计算钨球对半无限靶的侵彻深度,计算结果与试验相比最大误差20%(正误差15%,负误差5%),精度较刚性侵彻模型提升42.86%。     

球形破片侵彻有限厚靶板的模型建立与计算

描述了球形破片侵彻有限厚靶板的侵彻过程，建立了反映侵彻速度和侵彻深度间关系的分析模型．依据空穴膨胀理论计算侵彻阻力，依据Ａ－Ｂ模型将侵彻过程进行分解，并给出了各过程的侵彻方程，基于该模型研究了程序代码，以钨球对钢板、钨球对铝板分别模拟．球形破片对靶板进行了实例计算，并和试验结果进行了比较．     

钨合金圆筒爆破试验破片分布的统计分析

采用圆筒爆破试验方法研究了易碎型钨合金的破片分布特征,并与93W合金的结果进行了对比.对破片的数量和质量分布特征进行了统计分析,发现易碎型钨合金的破片率明显高于93W合金,而且破片的均匀性也明显好于93W合金,但易碎钨合金的破片回收率低于93W合金,而且受装药量的影响较大.     

增材制造316L不锈钢球形破片的弹道性能

为探索增材制造316L不锈钢球形破片的弹道性能,采用选择性激光熔化(Selective Laser Melting, SLM)技术制造316L不锈钢材料毛坯,通过机加工、抛光等操作得到了直径12 mm的增材制造316L不锈钢球形破片。开展打印态316L不锈钢材料的显微计算机断层扫描(Computed Tomography, CT)和静动态力学试验研究,获得了打印态316L不锈钢在材料沉积方向的Johnson-Cook(JC)模型参数,进行了增材制造和传统冷轧工艺制造的316L不锈钢球形破片侵彻6 mm厚Q235钢靶的弹道试验。研究结果表明：增材制造球形破片的弹道极限速度比传统冷轧制造破片低2.5%左右,弹道性能有小幅提升,暗示了增材制造工艺用于制造战斗部预制破片的潜力;开展的数值仿真研究获得了与试验结果一致的剪切冲塞穿靶机理,仿真与试验穿靶速度数据比较吻合,弹道极限速度误差仅为1.4%左右,仿真结果也表明JC模型用于描述增材制造316L不锈钢材料穿靶行为的可行性。     

钨锆铪活性合金破片冲击释能行为实验研究

为研究活性合金材料的冲击释能行为,采用弹道枪驱动一种高强度、高密度的钨锆铪活性合金破片,使其以不同着速撞击Q235钢靶,通过观察靶板穿孔模式和靶后冲击释能火光区的高速摄影图像,提出合金类破片冲击释能的3阶段模型,即冲击激活阶段、自蔓延释能阶段、自激活阶段。结合应力波、热应力理论和冲击温升方程,获得该破片能量的激活门限、能量完全释放的临界条件、释能火光区的最大尺寸及其靶后有效毁伤距离。研究结果表明：钨锆铪活性合金破片不仅具有类似惰性破片的动能毁伤能力,而且在穿靶前活性能耗极小,活性能量在穿靶后毫秒量级内完全释放;破片活性能量被完全激活前,释能火光区的最大毁伤容积和有效毁伤距离分别随破片着速的提高呈指数和线性增长趋势。     

钨合金破片高速穿甲工程计算方法探讨

为研究德马耳公式对合金破片穿甲性能的适用范围,采用该公式对钨合金球形破片在不同靶板厚度下的极限穿靶速度进行理论预测,采用数值模拟及靶试考核的方式对其验证。结果表明:由德马耳公式计算得出的极限穿靶速度,在靶板厚度为15 mm时,与数值模拟和靶试考核的结果一致;而靶板厚度为20 mm时不能侵彻靶板,与数值模拟和靶试考核结果差异较大。由此得出,德马耳公式适用于低速和高速下极限穿靶速度的预测,而对于超速穿甲具有一定的局限性。     

UHMWPE纤维二维织物抗弹道冲击性能

超高分子量聚乙烯(UHMWPE)纤维织物由于高模量、高强度、低密度等特点,被广泛应用于爆炸破片防护领域。基于Abaqus有限元分析方法,根据UHWMPE二维织物弹道冲击实验结果,建立UHMWPE二维织物的细观数值模型,并在细观纱线模型中考虑边界固定方式及尺寸效应的问题,同时开展弹道实验,对数值模型进行校正。鉴于细观纱线模型的纤维织物尺寸较小时对二维织物抗弹性能影响较大,而增加纤维织物尺寸带来了更多计算成本,建立细观-宏观混合尺度模型。该模型在提高计算效率的同时,其计算结果与实验结果具有良好的一致性。基于混合尺度模型,比较二维织物在不同头部形状弹丸(平头、尖头、球头)冲击下的弹道性能并与实验结果对比,主要评估参量为弹道极限和织物失效形式。结果表明：二维编织物抗平头弹冲击性能最优;在100 m/s以下的低速冲击下,抗尖头弹冲击性能较球头弹更优;在100 m/s以上的高速冲击下,抗球头弹冲击性能较尖头弹更优。     

刚性破片侵彻层合板运动模型

为揭示杀伤元与超高分子量聚乙烯(UHMWPE)层合板相互作用机制,开展硬质合金破片侵彻UHMWPE层合板的的弹道试验,获得不同入射速度下破片穿透层合板后的剩余速度以及层合板在不同速度下的断裂失效形貌特征。在此基础上,基于波动理论和能量守恒原理建立刚性破片对层合板侵彻过程的能量耗散模型,分析破片侵彻过程中不同形式能量传递规律。研究结果表明：侵彻过程中层合板因剪切失效、拉伸和压缩变形产生的能量传递在各种形式耗散能量中占主导地位;与试验结果对比发现,该模型可有效描述破片对层合板的侵彻过程,可为有防护目标杀伤机理及弹道设计提供一定参考。     

M855A1步枪弹侵彻钢靶板数值仿真

M855A1是一种采用新型穿甲弹结构的小口径步枪弹,较M855步枪弹主要优化了硬目标穿甲与软目标杀伤性能。为研究其穿甲性能,采用有限元软件ANSYS/LS-DYNA对不同射程下M855A1步枪弹侵彻结构钢靶板、装甲钢靶板的过程进行数值仿真,分析穿甲过程中弹头与钢靶板的变形和损伤演化,并对射程与极限穿透厚度的关系进行函数拟合,拟合精度高于99%。结果表明,M855A1步枪弹能基本满足现代小口径步枪弹对穿甲性能的需求,其结构在低速、薄靶条件下对弹体动能、质量的利用效率较高。     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Overview of Anti-tank Mines

First the different anti-tank mines laying possibilities are shortly summarized： hand emplaced, with mine layers, ground or helicopter relatively topographical well defined, and with cluster systems of projectiles, rockets and aircraft dispensers. Then examples of the three generations of anti-tank mines are presented：Ⅰ generation： detonating only beneath the track; Ⅱ generation： detonating beneath the track and belly; Ⅲ generation： mines with off-route actions. Weight and cost comparisons are strongly favoring the off-route Ⅲ-generation mines.     

A Finite Element Analysis on Static Strength of a Complex Section

A static finite element analysis （FEA） of an impulsive controller section is presented. The boundary condition and a part of the loads are applied. Considering the grades of the stress around the holes being large, the dense grids are adjusted accordingly. Four cases with different loads are compared, thus the influences of different loads on the section are analyzed. Numerical results show that the maximum stress of the section is lower than the strength limit of the material, and the section will not be broken with the static loads.