Three-dimensional reconstruction of precession warhead based on multi-view micro-Doppler analysis

The warhead of a ballistic missile may precess due to lateral moments during release. The resulting micro-Doppler effect is determined by parameters such as the target's motion state and size. A three-dimensional reconstruction method for the precession warhead via the micro-Doppler analysis and inverse Radon transform(IRT) is proposed in this paper. The precession parameters are extracted by the micro-Doppler analysis from three radars, and the IRT is used to estimate the size of targe. The scatterers of the target can be reconstructed based on the above parameters. Simulation experimental results illustrate the effectiveness of the proposed method in this paper.

Double casing warhead with sandwiched charge:The axial distribution of fragments velocities

The double casing warhead with sandwiched charge is a novel fragmentation warhead that can produce two groups of fragments with different velocity,and the previous work has presented a calculation formula to determine the maximum fragment velocity.The current work builds on the published formula to further develop a formula for calculating the axial distribution characteristics of the fragment velocity.For this type of warhead,the simulation of the dispersion characteristics of the detonation products at different positions shows that the detonation products at the ends have a much larger axial velocity than those in the middle,and the detonation products have a greater axial dispersion velocity when they are closer to the central axis.The loading process and the fragment velocity vary with the axial position for both casing layers,and the total velocity of the fragments is the vector sum of the radial velocity and the axial velocity.At the same axial position,the acceleration time of the inner casing is greater than that of the outer casing.For the same casing,the fragments generated at the ends have a longer acceleration time than the fragments from the middle.The proposed formula is validated with the X-ray radiography results of the four warheads previously tested experimentally and the 3D smoothedparticle hydrodynamics numerical simulation results of several series of new warheads with different configurations.The formula can accurately and reliably calculate the fragment velocity when the lengthto-diameter ratio of the charge is greater than 1.5 and the thickness of the casing is less than 20%its inner radius.This work thus provides a key reference for the theoretical analysis and the design of warheads with multiple casings.

Using Stochastic Colored Petri nets for Designing Multi-Purpose Plants

Designing of a multi-purpose plant as one of the well-known manufacturing systems is more challenging than other manufacturing systems. This paper applies a stochastic colored Petri net (CPN) to design and analyze multi-purpose plants. A simple approach is proposed to determine the utilization of shared resources and to reduce the equipment’s idle times. Three scenarios are presented to describe the proposed model. Generally, according to desire of a decision maker, different scenarios can be considered in the model to achieve to the expected design or plant configuration. The main characteristics of the proposed model are flexibility, the easiness of practical application and the simulation of the model in an easy way.

Water Quality Assessment of the Owena Multi-Purpose Dam, Ondo State, Southwestern Nigeria

Composite water samples taken from Owena Multi-purpose Dam in six sampling campaigns covering the wet and dry seasons were analyzed for physico-chemical and microbial characteristics using standard methods for the examination of water and wastewater jointly published by the American Public Health Association, American Water Works Association and Water Pollution Control Federation. Results showed significant (p < 0.05) seasonal variations in most measured parameters with few showing significant spatial variation. The characteristics of the water from the dam lake revealed an acceptable quality for most measured parameters with low chemical pollutants burden when compared with drinking water standards and water quality for aquaculture. However, high values of turbidity, colour, iron, manganese and microbial load were recorded compared with drinking water standards, which call for proper treatment of the water before distribution for public consumption.

Bias Effects on the Reynolds Stress Using the Multi-Purpose Probe in IR-T1 Tokamak

The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.

杀爆战斗部破碎形态及破片飞散特性数值模拟研究

针对战斗部威力与毁伤效能评估需求,采用FEM和SPH方法基于相同的结构尺寸和材料参数构建了某型杀爆战斗部的数值模型,研究了杀爆战斗部的弹体破碎形态及破片飞散速度沿轴线分布规律,同时对爆炸能量在各物质之间的传递及分配情况进行了计算。研究结果表明:SPH方法可以较好的模拟弹体裂纹扩展和破片生成,但在破片初速计算上,SPH方法忽略了爆轰产物加载过程,而FEM方法无法计算破片速度牵连作用,两者与试验结果相比分别偏低4.4%和7.5%,SPH方法可以更加准确反映爆炸能量在各物质之间的传递及分配规律,其中破片动能占爆炸总能量的36%,壳体拉伸、断裂的塑性变形能占爆炸总能量的5.7%。

两种钛合金半穿甲战斗部侵彻单层钢靶性能试验研究

选取亚稳态β型TB17和高损伤容限α+β型TC4-DT两种高韧钛合金材料,对2种钛合金材料在高应变率条件下动态力学响应特性进行测试分析,并应用125 mm火炮发射装置开展2种钛合金半穿甲战斗部侵彻单层钢靶性能试验研究。结果表明,作为半穿甲战斗部的壳体材料,应选择屈服强度与冲击韧性匹配性好的钛合金,其中更应关注钛合金材料的塑性变形能力和抗冲击韧性;随着侵彻着角的增加,侵彻单层钢靶过程弹体头部侵蚀量及径向墩粗程度更严重,不利于弹体保持侵彻强度及装药安定性。

加强筋位置对半穿甲战斗部侵彻多层钢靶性能影响研究

为了研究加强筋位置对半穿甲战斗部侵彻多层钢靶性能的影响,通过试验及数值仿真,研究了加强筋在弹体轴向不同位置处的2种半穿甲战斗部,以一定速度(710 m/s)、着角(20°)侵彻8层钢靶的弹道偏转、弹孔尺寸、余速的差异。研究结果表明:加强筋位置由弹尖向质心位置逼近时弹道偏转角减小、弹孔长轴减小、穿甲能力提升;弹道偏转角增量与靶间距呈正相关关系;弹道偏转角、侵彻余速、弹头侵蚀量及弹孔仿真结果与试验实测值最大偏差为8.82%,仿真与试验结果符合较好。研究结果可为半穿甲战斗部方案设计提供参考。

应用差分进化-神经网络模型的杀爆弹瞄准点分配方法

为在不增加计算时耗的前提下提升多枚杀爆弹对面目标打击毁伤效能,建立融入动爆威力计算的多瞄准点规划方法.对面目标采用结构化网格划分方法实现多枚杀爆弹对目标毁伤区域的精确计算,并进行计算结果验证,基于多次计算结果采用神经网络方法建立单枚弹药对面目标毁伤区域的计算代理模型,在同样计算条件下,比非代理模型计算时间缩短1000倍;据此,通过差分进化算法实现多枚杀爆弹对面目标打击瞄准点及末端弹道参数的规划.通过实例对比分析表明:该瞄准点规划方法形成的打击方案比传统以毁伤半径为输入的方法毁伤效果大幅提升,最低提升25.5%,且单次规划时间不超过3 s,解决了瞄准点规划中毁伤效能模型复杂度与计算耗时之间的矛盾.

战斗部破片光电测速系统设计

战斗部破片的飞行速度是体现其性能指标的重要参数;针对目前在战斗部破片速度参数测试中存在对测试环境要求高,测试面积小,设备结构易被破片误击而损坏,成本昂贵等问题,设计了非接触式战斗部破片光电测速系统,包含原向反射膜、反射式光电探测装置、光电转换电路、信号处理电路及测速装置;阐述了系统结构组成和测速原理,通过反射式光电探测装置与光电转换电路,将得到的光信号转换为电信号,利用集成信号处理电路对电信号滤波放大,比较整形处理,由FPGA,STM32及其他外设组成的测速装置自动处理数据输出并显示战斗部破片的飞行速度结果;实验结果表明:该系统能够可靠,稳定地完成战斗部破片速度的测量任务;与传统测速系统相比,具有不受限于环境,测试区域大,易维护,低成本,操作简单等优势。

战斗部头部形状对侵彻钢板影响的试验与理论研究

[目的]旨在探究战斗部头部形状对其侵彻匀质金属板性能的影响。[方法]利用92 mm滑膛炮发射平头型战斗部和尖头型战斗部侵彻Q345B与921A钢材料的靶板,通过测速靶网以及高速摄像方法对战斗部侵彻钢板前后的速度进行测量,分析侵彻靶板后战斗部与靶板的毁伤模式,从而建立起不同头部形状战斗部侵彻下的理论评估方法。[结果]结果表明:战斗部头部形状对侵彻靶板后的毁伤模式以及对不同类型钢板的等效换算均具有重要影响;尖头型战斗部对靶板的毁伤以花瓣型为主,平头型战斗部以剪切冲塞为主;与贝尔金公式相比,采用改进Thomoson公式计算战斗部侵彻靶板后的剩余速度所得结果与试验结果吻合更好。[结论]所提方法及结果可用于后续对战斗部穿甲性能的评估,并可为后续大质量战斗部侵彻金属板研究提供相关依据。

锥形头战斗部动态爆炸破片载荷特性分析

为探究锥形头战斗部在不同运动速度下破片的载荷特性,采用SPH仿真方法模拟锥形头战斗部壳体膨胀形成破片的过程和破片载荷特性,并与静爆试验结果对比,验证数值仿真模拟的准确性,研究锥形头战斗部不同运动速度对破片载荷特性的影响。结果表明,战斗部首端部由于截锥面的存在,提高了端部的破片分布区域,增加了战斗部破片的打击范围;战斗部壳体形成的破片初速度沿战斗部轴向呈现明显的阶梯形分布,基于此破片速度可分为四个区域:截锥壳体部、圆柱壳体中前部、圆柱壳体中部和圆柱壳体中后部;动爆条件下,随着战斗部运动速度的增加,尾端部壳体形成的破片初速度呈现出先减小后增大的不规则“V”形,破片飞散角受战斗部运动速度的影响较小,破片飞散方位角沿着战斗部运动方向移动。

导弹战斗部装药质量监督要点研究

针对导弹战斗部装药质量监督的实际需求,分析目前战斗部典型装药工艺方法(熔铸装药、压装药、PBX浇注装药)的特点。经过对比分析,结合导弹战斗部的发展需求,提出装药质量监督要点,为战斗部装药质量监督拟定较详细的控制措施。结果表明:该质量监督要点及控制措施,可有效指导相关人员把控战斗部装药质量,提高监管效能。

圆柱-双锥结合药型罩结构参数对侵彻性能的影响规律

为提高聚能破甲战斗部的毁伤能力,设计了一种圆柱-双锥结合药型罩。用数值模拟方法,通过对该药型罩的正交优化设计,研究了药型罩圆柱部直径d、高度h、上锥角α、下锥角β对射流头部速度和侵彻深度的影响。研究结果表明,上锥角和圆柱部直径分别是影响射流头部速度和侵彻深度的主要因素。因此,在优化设计中得到了兼顾射流速度和侵彻深度的最佳药型罩结构:d=8 mm、h=12 mm、α=36°和β=56°时,射流头部速度为8 667 m/s,侵彻深度达到173.7 mm。优化设计的研究结果具有一定的实际工程指导意义,可为聚能破甲战斗部的性能提升提供有效的设计方案。

串联战斗部级间隔爆结构的研究现状和发展趋势

串联战斗部作为反爆炸反应装甲的一个重要手段,已成为国内外兵器研究的热点。串联战斗部工作时,前级装药爆炸势必对后级装药产生影响。为削弱前级装药爆炸产生的爆轰波与碎片对后级装药的影响,需要在前后级装药之间设置隔爆结构。良好的隔爆结构对串联战斗部前后级稳定工作,提升战斗部性能有重要意义。综述了近年来串联战斗部级间隔爆体的研究进展,包括结构布局、材料选型与优化设计方法等方面,并结合目前隔爆体发展状况对隔爆体未来发展趋势进行展望,以期对串联战斗部隔爆体的设计和改进有所启示。

某串联战斗部级间隔爆体结构的优化设计

为实现串联战斗部级间隔爆体结构减重,利用有限元分析软件LS-DYNA建立了某型前级战斗部与隔爆体的数值仿真模型,采用正交试验的方法,研究级间锥形隔爆体前锥角,倒角与前后锥角差值对隔爆体质量的影响规律。结果表明:隔爆体的前锥角对隔爆体质量影响显著,前后锥角差次之,倒角影响较弱。利用正交优化方法,设计三因素四水平的正交优化方案,结果表明当,r=9.9 mm,时,隔爆体的质量最低为485.40 g。研究成果可为串联战斗部隔爆体的结构设计和优化提供指导。

周向六线起爆下杀伤战斗部的破片飞散特性

为简化起爆结构,提高引战系统可靠性,采用定向战斗部已有的周向六线起爆方式替代中心起爆,基于流体动力学理论对周向六线起爆下爆轰波的碰撞进行了理论分析,采用LS-DYNA进行了数值计算,并开展了战斗部样弹静爆试验。结果表明,相较于中心起爆,周向六线起爆条件下破片加速历程与其所在周向位置存在关联,并出现二次加速现象;在相邻起爆点对称面附近产生马赫爆轰波,局部压力可达44.2GPa,并在战斗部中心汇聚,中心处压力可达100GPa以上;轴向多点起爆改善了端面稀疏波的影响,破片速度得到提升,轴向破片速度一致性明显提高;破片飞散初速数值计算与试验结果误差在8.1%以内,不同区域破片初速增益可达4.6%~9.9%。表明周向六线起爆模式是替代定向杀伤战斗部中心起爆模式的有效途径。

不同组合式聚能战斗部对水下目标的毁伤研究

为研究不同组合药型罩聚能型鱼雷战斗部对含水复合结构的穿透性能,建立了聚能装药侵彻含水复合结构的数值计算模型,分析了射流成型过程和穿靶过程。结果表明:圆柱-球缺组合罩相比于其他2种组合药型罩对含水复合结构的穿透性能更好,对后效靶造成的穿深最大。圆柱-球缺组合罩形成的射流长度相比于其他2种组合药型罩分别长10.4%和28.9%,头部速度分别高20.6%和54.3%。侵彻含水复合结构时,圆柱-球缺组合罩形成的水下空腔、水介质径向扩展速度均最小,所以在侵彻含水复合结构后得以保留最大的剩余动能,从而对后效靶造成的穿深最大。合理匹配圆柱-球缺药型罩圆柱部直径d和高度h可提升其对含水复合结构的穿透能力,当d=22 mm、h=16 mm时,圆柱-球缺组合罩可对后效靶取得最大穿深411 mm。结论可为聚能型鱼雷战斗部的组合药型罩选择提供参考。

装液战斗部液体分散的数值仿真与试验研究

通过建立典型战斗部结构在不同驱动压力、不同动力黏度液体工况下的液体分散流体动力学仿真模型,对战斗部壳体的受力情况进行计算分析,仿真计算结果与试验测试数据对比可知,计算模型可为该装液战斗部壳体的受力规律分析提供支撑。建立了战斗部壳体内部压力测试系统,获得壳体内部轴向的不同部位的压力时程曲线和压力峰值,得出战斗部壳体内部由于压力波的叠加导致战斗部内部壳壁的峰值均高于驱动压力值,位于喷射孔近区的战斗部壳体承受压力值最大,随着与喷射孔距离的增加,压力峰值随之下降;火药产生的驱动压力和液体动力黏度与战斗部壳体的压力值均正相关。

多点起爆下鼓形战斗部的威力特性

为调控对地弹药破片杀伤威力场,研究了一种鼓形战斗部在静爆和动爆下的威力特性。采用数值模拟研究了端面中心单点、中心单点两种起爆方式下,鼓形战斗部相较于同口径圆柱形战斗部在静爆下的破片威力特性及动爆下对地面装甲车辆目标的毁伤面积。在此基础上,调整鼓形战斗部起爆方式为偏心两线同时起爆、偏心两线序贯起爆及偏心两线同时-序贯起爆,计算了不同偏心起爆下鼓形战斗部静爆时的破片速度、飞散角和动爆时对车辆目标的毁伤面积及有效破片落地动能分布。研究表明,相比于同口径的圆柱形战斗部结构,鼓形战斗部的破片飞散角增大了55.98%,对地面军用车辆的毁伤面积最大增大了59.3%;相对于偏心两线同时起爆,偏心两线同时-序贯起爆的鼓形战斗部破片飞散角增大了18.0%,破片飞散的离散程度提高了11.48%;相对于装药中心单点起爆,偏心两线序贯起爆下鼓形战斗部的毁伤面积受炸高影响较小,在落角50°、落速200 m/s、炸高为9 m时的毁伤面积达47.15 m^(2)。通过调整战斗部的结构和起爆方式,可有效增大破片的飞散角,增大破片对目标的覆盖面积,提高战斗部的毁伤效能。