基于能力的地面无人作战系统作战效能试验评估方法

作战效能试验评估是检验地面无人作战系统是否满足作战要求的根本手段.针对地面无人作战型号新、作战需求牵引性弱等问题,紧贴地面无人作战系统的智能自主特性,以能力构想为核心,以作战概念创新为牵引,建立了基于能力的地面无人作战系统作战效能试验评估框架,明确了作战概念设计的主要内容和关键技术,提出了地面无人作战系统的作战效能试验方法,设计了地面无人作战系统的作战效能指标框架和总体方案,为适应地面无人作战系统发展要求,并有效开展作战效能试验评估提供了科学方法.     

新型人机交互技术在指控系统的应用

人机交互技术对指控系统的高效运行和安全可靠至关重要.面向未来指控系统的人机交互需求,阐述了指控系统人机交互技术的发展方向和应用现状,总结了目前指控系统人机交互环节存在的4种局限性.在此基础上,提出将沉浸式交互、多通道交互、人机融合智能交互、情感计算4种新型人机交互技术应用于下一代指挥控制系统,以此来提高指挥控制过程的自然性、高效性和可靠性.该成果为新型人机交互技术在指控系统的研究和应用提供了相关理论支撑.     

Fabrication and analysis of TIG welding-brazing butt joints of in-situ TiB2/7050 composite and TA2

Lightweight hybrid structures of Al MMCs and titanium alloy dissimilar materials have great prospect in the defence industry application. So, it is necessary to join Al MMCs with Ti metal to achieve this structural design. In this work, in-situ TiB2/7050 composite and TA2 were firstly attempted to join by TIG welding-brazing technique. The result was that the intact welding-brazing butt joint was successfully fabricated. The joint presents dual characteristics, being a brazing on TA2 side and a welding on TiB2/7050 side. At brazing joint side, ER4043 filler metal effectively wets on TA2 under TIG heating condition, and a continuous interfacial reaction layer with 1—3μm is formed at welded metal/TA2 interface. The whole interfacial reaction layers are composed of Ti(AlSi)3 intermetallic compounds (IMCs), but their morphologies at the different regions present obvious distinguishes. The microhardness of the reaction layers is as much as 141—190 HV. At welding joints side, the fusion zone appears the equixaed crystal structure, and the grain sizes are much smaller than those of welded metal, which is attributed to the effect of TiB2 particulates from the melted TiB2/7050 on acceleration formation and inhibiting growth for the new crystal nucleus. The tensile test results show that average tensile strength of the optimal welding-brazing joint is able to achieve 138 MPa. The failure of the tensile joint occurs by quasi-cleavage pattern, and the cracks initiate from the IMCs layer at the groove surface of TA2 and propagate into the welded metal.     

Research on the intermediate phase of 40CrMnSiB steel shell under different heat treatments

In this study, 40CrMnSiB steel cylindrical shells were tempered at 350, 500 and 600 ℃ to study the effect of tempering temperature on the dynamic process of expansion and fracture of the metal shell. A mid-explosion recovery experiment for the metal cylinder under internal explosive loading was designed, and the wreckage of the casings at the intermediate phase was obtained. The effects of different tempering temperatures on the macroscopic and microscopic fracture characteristics of 40CrMnSiB steel were studied. The influence of tempering temperatures on the fracture characteristic parameters of the recovered wreckage were measured and analyzed, including the circumferential divide size, the thick-ness and the number of the circumferential divisions. The results show that as the tempering temper-ature was increased from 350 to 600 ℃, at first, the degree of fragmentation and the fracture characteristic parameters of the recovered wreckage changed significantly and then became essentially consistent. Scanning electron microscopy analysis revealed flow-like structure characteristics caused by adiabatic shear on different fracture surfaces. At the detonation initiation end of the casing, fracturing was formed by tearing along the crack, which existed a distance from the initiation end and propagated along the axis direction. In contrast, the fracturing near the middle position consists of a plurality of radial shear fracture units. The amount of alloy carbide that was precipitated during the tempering process increased continuously with tempering temperature, leading to an increasing number of spherical carbide particles scattered around the fracture surface.     

Simulation of the plasticizing behavior of composite modified double-base (CMDB) propellant in grooved calendar based on adaptive grid technology

The frequent occurrence of safety accidents during the calendering process is caused by the flammable and explosive properties of composite modified double-base (CMDB) propellant. Optimization of process parameters with the aid of fluid simulation technology could effectively ensure the safety of the calendering process. To improve the accuracy of the simulation results, material parameters and model structure were corrected based on actual conditions, and adaptive grid technology was applied in the local mesh refinement. In addition, the rheological behavior, motion trajectories and heat transfer mechanisms of CMDB propellant slurry were studied with different gaps, rotational rates and temperatures of two rollers. The results indicated that the refined mesh could significantly improve the contour clarity of boundaries and simulate the characteristics of CMDB propellant slurry reflux movement caused by the convergent flow near the outlet. Compared with the gap, the increased rotational rate of roller could promote the reflux movement and intensify the shear flow of slurry inside the flow region by viscous shear dragging. Meanwhile, under the synergistic effect of contact heat transfer as well as convective heat exchange, heat accumulated near the outlet and diffused along the reflux movement, which led to the countercurrent heat dissipation behavior of CMDB propellant slurry. The plasticizing mechanism of slurry and the safety of calendering under different conditions were explored, which provided theoretical guidance and reference data for the optimization of calendering process conditions. Based on the simulation results, the safety of the CMDB propellant calendering process could be significantly improved with a few tests conducted during a short research and development cycle.     

Formation and characterization of core-shell CL-20/TNT composite prepared by spray-drying technique

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene (CL-20/TNT) composite was prepared by spray-drying method in which sensitive high energy explosive (CL-20) was coated with insensitive explosive (TNT). The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Laser particle size analyzer, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impact sensitivity test and detonation performance. The results of SEM, TEM, XPS and XRD show that ϵ-CL-20 particles are coated by TNT. When the ratio of CL-20/TNT is 75/25, core-shell structure is well formed, and thickness of the shell is about 20–30 nm. And the analysis of heat and impact show that with the increase of TNT content, the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material (CL-20), but also greatly reduce the impact sensitivity. Compared with the CL-20/TNT mixture (75/25) at the same ratio, the characteristic drop height of core-shell CL-20/TNT composite (75/25) increased by 47.6% and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT composites. Therefore, the preparation of the core-shell composites can be regarded as a unique means, by which the composites are characterized by controllable decomposition rate, high energy and excellent mechanical sensitivity and could be applied to propellants and other fields.     

Effect of projectile parameters on opening behavior of PELE penetrating RC target

When a penetrator with enhanced lateral effect (PELE) impacts on a reinforced concrete (RC) target, the target is damaged with a large opening. An understanding of how PELE projectile parameters affect the opening dimension, is essential for effective design of the PELE projectile. In this study, under the condition that the impact velocity and target parameters (strength and thickness) were fixed values, the important influence factors of the PELE (jacket wall thickness B, jacket material strength Y1, filling material strength Y2 and angle of monolithic jacketθ) were determined by a dimensional analysis. Tests and simulations of the PELE penetrating the RC target were conducted to analyze the influence of these factors on opening diameter ((D), an equivalent diameter under relative kinetic energy). Based on the test and simulation results, it is found that the influence of these factors B, Y1 andθon the deformation mode of the jacket shows a similar trend:as values of the three factors decrease, the jacket deforms from small bending deformation to large one, and then to curling deformation. This causes the opening diameter to first increase with the decrease of these three factors, and then decreases. It is well known that the bending resistance of the jacket is related to these factors B, Y1 andθ. Therefore, a plastic limit bending moment (M0) of the jacket was quoted to characterize the influence of these factors on the bending deformation of the jacket and the opening diameter of the target. The influence factor Y2 causes (D) to first increase with the increase of Y2, and then decreases. A formula was developed to predict the opening diameter, whose influence parameters were considered in a dimensionless way. It has been shown that the dimensionless opening diameter (D)/d1 is dependent on two dimensionless parameters Q = (d31fc/M0) and G = (fc/Y2), where d1 and fc are the outer diameter of the projectile and the compressive strength of the target, respectively.     

Evaluation of infrared camouflage effectiveness via a multi-fractal method

This paper reports an alternative approach to the evaluation of infrared camouflage effectiveness via a multi-fractal method. By calculating multi-fractal spectra of the target region and the background re-gions in an infrared image, the spectrum shape features and the discrete Fréchet distances among these spectra were used to analyze the camouflage effectiveness of the target qualitatively and quantitatively, and the correlation coefficients of the spectra were further used as the index of camouflage effectiveness. It was found that the camouflaged target had better camouflage effectiveness than the target without camouflage in the same one background, and the same one camouflaged target had different camouflage effectiveness in different backgrounds. On the whole, the target matching well with its background had high camouflage effectiveness value. This approach can expand the application of multi-fractal theory in infrared camouflage technology, which should be useful for the research of infrared camouflage mate-rials, the design of camouflage patterns as well as the deployment of military equipment in battlefield.     

Improving the damage potential of W-Zr reactive structure material under extreme loading condition

Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gun-powder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propa-gation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops the W-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.     

听力教学中“环境训练法”的实验研究

本文就学生在听力技能训练中普遍存在较为突出的问题:大脑疲劳与精神紧张,从心理学和生理学的角度提出了"环境训练法".其目的是通过放松练习来改善大脑环境从而使学生在轻松愉快的状态下积极高效地练习听力.通过实验对比与分析,实验组与对照组相比p<0.01,实验组听力成绩明显优于对照组.实验研究证明这一方法具有实用性与有效性.