Research on the Fracture Mechanism of Scored Liner Under Explosive Loading

The notch tip fracture criterion of cored liner is proposed based on a dislocation model. The analysis reveals that the ductile shear fracture is a dominant fracture mode in the scored liner, and the fracture path is along the maximum shear stress tracing line. The numerical simulation of fracture process of scored liner under explosive loading is performed using the nonlinear finite element analysis program ANSYS-LS/DYNA, and then the experiments are made to verify the simulation. The experimental results are demonstrated to be in line with the numerical simulation results. The liner can form a focused jet of metal fragments with certain amount and mass that travels at very high speed in the cone-angle direction, which indicates that the dislocation model can be used to analyze the crack fracture of notch tip.     

Numerical Simulation on New Perforator

To study a new shaped charge of perforator, the jet formation and penetration processes in concrete targets are simulated numerically by using LS-DYNA finite element analysis software. The results show that the cylindrical liner can form jet and most materials on top of liner form the tip of jet, while the others form the tail of jet. The jet has a better continuity, and the ratio of cumulative jet length to the liner diameter can reach to 7.56. Furthermore, the ratio of bore diameter to the liner diameter is from 0.36 and 1, and the ratio of penetration depth to the liner diameter can be up to 5.5.     

Research on Matching Relationship Between Number of Initiation Points and Charge Diameter

For shaped charges,LS-DYNA software was adopted to explore the influence of number of initiation points on the penetrator formation numerically.Changed the number of initiation points from 4 to 36,the performance of penetrator under four different kinds of typical charge diameter was analyzed,and the effect of detonation wave pressure on the liner was discussed.The minimum number of initiation points to substitute for annular initiation was obtained for each of four warheads with different charge diameters,and the curve representing the relation between the number of initiation points and charge diameter was found out also by using polynomial fitting.The simulation result provides a reference for the design of multimode warhead.     

Research on the Application of Explosive Network in the Shaped Charge Warhead

With respect to the problems of that the shaped charge warhead currently uses a cover method to improve the penetration power, a method using an explosive network technology as the detonation mode of shaped charge warhead is proposed. In the context of some shaped charge warhead, a synchronous explosive network prototype is designed according to some charge structure parameters, such as the liner and main grain. From the performance comparison test, it can be known that the explosive network not only stably detonates, but also largely improves the penetration power and stability. Experimental results show that explosive network technology is an effective method for improving the penetration power. The results lay a solid foundation for the engineering application of the technology in the shaped charge warhead.     

Simulation and Experimental Investigation of Jetting Penetrator Charge at Large Stand-off Distance

In order to study and apply the penetration performance of jetting penetrator charge at long stand-off distance, three jetting penetrator charges （JPC）, including spherical cone liner, truncated wide-angle liner and spherical segment liner, are designed. The numerical simulation analysis of the formation, elongation and penetration processes of rod-like jet is conducted by using LS-DYNA software. And the penetrating test is carried out at long stand-off distance. The test results show that the rod-like jet formed by the optimized spherical segment liner can pierce through a 90ram thick 45# steel target at 20 charge diameters（ CD ） stand-off distance when the charge detonation mode is a central point initiation, and the penetration depth can be up to 1.6CD. It is concluded that, at 20 CD stand-off distance, the penetration performance of JPC with spherical segment liner is the best, that of truncated wide-angle liner takes second place, and that of spherical cone liner is the worst.     

Influence of Structure Parameters of Double-angle Liner on Jet Formation

By using LS-DYNA simulation software,the influences of some structure parameters,such as top cone angle,wall thickness,liner height and height ratio of top cone,of double-angle liner on the jet formation were studied respectively.Their influences on jet tip velocity,tail velocity and penetration depth were revealed.The simulation results show that the formation is better if the top cone angle is selected as 28°,the wall is 2.6mm,the liner height is 140mm,and the height ratio of top cone is 60%.In large stand-off distance,the jet has a higher tip velocity,and the tip does not break.With the stand-off distance of 8 times of the charge diameter,the experiment penetrating steel target was carried out.The experiment and simulation results are in good agreement.     

Design and Implementation of One Missile Visual Simulation System Based on OpenGL

The implementation of a missile＇s visual simulation system is explained that is developed with OpenGL（open graphic library） and the flight path and flight carriage in different stages of the missile are displayed. The establishment problems of the 3D scene are circumstantiated including the construction and redeployment of the model, creation of the virtual scene, setting of the multi-viewports and multi-windows etc. The missile＇s data driver, system flow, the modules and their mutual relations of the missile visual simulation system are discussed. The missile flight simulation results and effect of the scenes are given.     

Study on Effects of Diesel Engine Cooling System Parameters on Water Temperature

A simulation model for a certain diesel engine cooling system is set up by using GT-COOL. The backwater temperature response in different operating conditions is simulated numerically. The effects of single or multiple system parameters on the water temperature are analyzed. The results show that, changing different single parameters, the time taken for the steady backwater temperature is different, but relatively short;and if multiple parameters are changed, the time will be longer. Referred to the thermal balance test, the simulation results are validated and provide a basis for the intelligent control of the cooling system.     

Application of Adaptive Backstepping Sliding Mode Control in Alternative Current Servo System of Rocket Launcher

An adaptive backstepping sliding mode control approach is introduced to control the pitch motion of a rocket launcher. Its control law is proposed to guarantee that the control system is ultimately bounded in a Lyapunov sense and make the servo system track the instruction of reference position globally and asymptotically. In addition, the sliding mode control can restrain the effects of parameter uncertainties and external disturbance. The functions of adaptive mechanism and sliding mode control are analyzed through the simulation in the different conditions.The simulation results illustrate that the method is applicable and robust.     

Study of simple plane wave generator with an air-metal barrier

Plane wave generators （PWGs） are used to accelerate flyer plates to high velocities with their generated plane waves, which are widely used in the test of dynamic properties of materials. The traditional PWG is composed of two explosives with different detonation velocities. It is difficult to implement the related fabrication processes and control the generated waves due to its complicated structures. A simple plane wave generator is presented in this paper, which is composed of two identical cylindrical high explosive （HE） charges and an air-metal barrier. A theoretical model was established based on two different paths of the propagation of detonation waves, based on which the size of air-metal barrier was calculated for a given charge. The corresponding numerical simulations were also carried out by AUTODYN-2D based on the calculated results, which were used to compare with the theoretical calculations. A detonation wave with a flatness of 0.039 μs within the range of 70-percent diameter of the main charge was obtained through the simulations.     

药型罩锥角对聚能杆式侵彻体影响的数值分析

为研究药型罩锥角对聚能杆式侵彻体的影响,运用AUTODYN 软件建立聚能装药模型,对90?～130?大 锥角药型罩形成的聚能杆式侵彻体进行数值模拟。建立装药结构有限元模型,研究不同锥角药型罩形成的聚能杆式 侵彻体在同一时刻、同一炸高下的成型情况,分析在5 倍装药口径炸高条件下聚能杆式侵彻体对均质靶板的侵彻情 况,得到在装药口径和高度一定的前提条件下,药型罩锥角对聚能杆式侵彻体成型参数的影响规律。研究结果表明： 药性罩锥角在100?～110?时,形成的聚能杆式侵彻体具有较好的连续性、稳定性与侵彻性能,可为聚能杆式侵彻体 战斗部的设计及应用提供参考。     

药型罩锥角对聚能杆式侵彻体影响的数值分析

为研究药型罩锥角对聚能杆式侵彻体的影响,运用AUTODYN 软件建立聚能装药模型,对90?～130?大 锥角药型罩形成的聚能杆式侵彻体进行数值模拟。建立装药结构有限元模型,研究不同锥角药型罩形成的聚能杆式 侵彻体在同一时刻、同一炸高下的成型情况,分析在5 倍装药口径炸高条件下聚能杆式侵彻体对均质靶板的侵彻情 况,得到在装药口径和高度一定的前提条件下,药型罩锥角对聚能杆式侵彻体成型参数的影响规律。研究结果表明： 药性罩锥角在100?～110?时,形成的聚能杆式侵彻体具有较好的连续性、稳定性与侵彻性能,可为聚能杆式侵彻体 战斗部的设计及应用提供参考。     

一种超聚能装药结构的仿真

为了得到一种新型的可形成较传统射流更高速度的聚能装药结构,利用非线性动力学分析软件AUTODYN-2D对其成型过程进行了数值仿真,并应用应力波基础、冲击力学等相关理论进行分析。研究表明：选用铜、钽、钨作为“蘑菇形”药型罩的材料可以得到速度在8800～13000 m／s且具有良好成型效果的高速射流。分析了药型罩壁厚和下辅助药形罩二的半径结构参数对射流速度的影响,结果表明,减小药型罩厚度或增大下辅助药形罩的半径可以有效提高形成射流的速度,但速度超过13700 m／s后成型效果变差。根据研究成果可以得到“蘑菇形”药型罩各部分材料的搭配规律及其成型规律。     

基于BP神经网络和遗传算法的环形药型罩优化

环形聚能装药相比传统的聚能装药具有侵彻口径大的优势,为了得到可以形成稳定的环形聚能射流的最优环形药型罩结构,提出了一种将数值模拟结果与BP神经网络相结合,并通过遗传算法对环形药型罩进行优化设计的方法。首先,利用正交试验法对环形药型罩进行方案设计,得到各因素对环形聚能射流稳定性的重要程度,其次利用LS-DYNA软件进行数值模拟得到最初的样本数据,然后通过MATLAB软件拟合出神经网络训练所需的样本数据,接着将环形药型罩结构参数作为BP神经网络的输入,射流头部速度、射流横向速度、射流长度分别作为输出进行训练,同时将测试值作为适应度,最后结合遗传算法选择最优的环形药型罩结构参数。研究结果表明:影响环形聚能射流成形的主要因素是药型罩口径和锥顶角,次要因素为药型罩罩顶厚、内罩偏移量和外罩偏移量; 当药型罩罩顶高为0.81 mm,药型罩口径为15.43 mm,罩顶角为61.89°,内罩偏移量为11.38%,外罩偏移量为14.36%时所形成的环形射流形态比正交实验所得环形聚能射流更好。     

应用数值模拟和灰色理论计算分析聚能装药参数对聚能侵彻体成型性的影响

通过数值模拟研究了药型罩及装药参数对聚能射流成型性能的影响,在此基础上,运用灰关联理论对影响侵彻体性能的各个参数的灰关联度进行了分析。结果表明,药型罩高度、壁厚、锥角、装药高度是影响侵彻体成型性能的主要因素,改变药型罩高度可以实现对侵彻体成型性的控制,药型罩壁厚对侵彻体最后成型产生较大影响,药型罩锥角可以有效控制侵彻体头部和尾部速度差,灰关联分析结果可以作为药型罩设计中优先考虑的重要参数。     

射流侵彻混凝土介质数值模拟及影响因素研究

利用Ansys/LS-DYNA有限元分析软件,对聚能射流侵彻混凝土介质的全过程进行了数值模拟,模拟结果与实验数据基本吻合。通过数值模拟计算重点分析了药型罩锥角、药型罩厚度、壳体厚度、炸高和装药长度对聚能射流侵彻效能的影响规律。研究结果表明：药型罩锥角、药型罩厚度和炸高对聚能射流的侵彻深度和侵彻孔径影响较大,而壳体厚度和装药长度对侵彻效能影响较小。     

贴隔板法在尾翼EFP成型中的应用研究

采用LS—DYNA对在药型罩上粘附隔板结构形成带尾翼型爆炸成型弹丸（explosively formed projeetile，EFP）进行三维数值模拟，从药型罩微元压跨速度和压力的角度初步探讨了形成尾翼型EFP的机理，对同一直径的大锥角型、球缺型和弧锥结合型药型罩形成的尾翼型EFP进行了对比分析，三种结构药型罩均能形成较为明显的尾翼，其中大锥角型药型罩得到的EFP速度最高。数值计算结果表明，EFP尾翼数与药型罩上所粘贴的隔板数一致，三种不同结构药型罩上粘贴四个隔板，得到的尾翼数均为四个。通过实验，对贴隔板法形成尾翼EFP做了进一步验证，实验结果与数值模拟结果基本一致。     

聚能装药超细晶纯铜药型罩性能研究

为了实现真正意义上的超细晶,利用剧烈塑性变形的方法将纯铜材料的晶粒组织进行细化.应用ANSYS/LS-DYNA有限元软件对粗晶纯铜药型罩和超细晶纯铜药型罩形成的射流侵彻45钢靶板过程进行数值模拟.分析晶粒尺寸对于射流断裂时间的影响,研究在不同炸高条件下,超细晶纯铜药型罩和粗晶纯铜药型罩侵彻威力的差异,以及炸高对于2种材料形成射流延展性的影响,并通过选取粗晶纯铜药型罩的最佳炸高进行静破甲试验研究,验证了数值计算结论的可靠性.研究结果表明:在炸高相同的前提下,超细晶纯铜药型罩形成的射流毁伤能力较粗晶纯铜药型罩而言,有大幅提升,说明将药型罩材料晶粒尺寸细化,是提高聚能射流破甲威力的有效手段.     

大锥角药型罩聚能装药结构对混凝土介质侵彻研究

采用脉冲X光照相、威力效应实验及数值模拟方法,对两种不同形状的大锥角药型罩聚能装药结构对混凝土的侵彻能力进行了研究,实验测试获得了大锥角截顶药型罩装药结构形成的爆炸成型杆式侵彻体的形状、头尾速度及对混凝土靶的侵彻参量;采用AUTODYN-2D程序对两种结构药型罩聚能装药的成形过程和侵彻过程进行了数值模拟.结果表明,相比于大锥角截顶药型罩,大锥角球缺型药型罩所形成的爆炸成型杆式侵彻体在混凝土靶中形成的孔道更能满足复合侵彻战斗部对一级侵彻的要求.     

ー种新型星锥状药型罩形成射流的数值模拟

研究一种新颖的星锥形药型罩结构，它是在楔形药型罩基础上，通过改变装药结构而演化出的一种星锥状聚能装药结构，由若干个楔形药型罩对称排列且向一端聚合而成。应用非线性有限元软件完成了爆炸载荷下星锥药型罩形成射流过程的数值模拟，结果表明，新型药型罩能够实现预期设想，形成一股凝聚射流。研究结果为新型破甲装药结构研究提供了一种新的选择，在反装甲弹药战斗部领域具有良好的应用前景。