金属材料的超高速刨削研究进展

综述国外40多年来金属材料超高速刨削研究进展情况。从试验研究和仿真研究两方面总结和分析了速度、材料特性、冲击角度等因素对超高速刨削的影响,重点阐述了刨削冲击形成机理及刨削抑制方法的研究现状。提出了下一步发展方向的建议。     

电磁轨道发射器刨削产生特征与研究现状

超高速刨削是超高速滑动下轨道表面的一种损伤形式。刨削的出现降低系统发射效率、缩短轨道寿命,增大射弹方向误差。从刨削产生规律、刨槽形貌特性和发生发展物理机制3个方面,较全面的总结轨道上超高速刨削损伤的研究现状。结合轨道炮特有的超高速大电流特性,展望轨道炮抑制刨削的研究趋势。     

电磁轨道炮轨道表面刨削产生分析

刨削是一种高速滑动过程中发生在接触界面的损伤现象.对电磁轨道炮超高速滑动电接触界面刨削形成的因素进行了探讨,对刨削产生的微观机械作用过程进行了详细的分析,得出刨削发生于一个高速高温高应变率的物理环境中;刨削过程的物理实质是电枢与轨道局部微凸体发生了绝热塑性剪切作用.最后归纳了目前抑制刨削的3种手段,为轨道炮系统结构的设计提供了参考.     

大电流高速滑动刨削的预测模型

轨道加速装置利用电能可以将物体加速到超高速,在高速滑动过程中会对轨道装置接触面造成刨削的损伤。刨削的出现会影响发射效果和降低装置寿命。考虑到轨道发射装置具有大电流和超高速度的特性,提出了一种新的刨削预测模型——电枢电动力驱动功率模型,在此主要通过紫铜电枢-紫铜轨道配对的不同电枢加速模式来验证预测模型的准确性,分析试验结果得到电枢电动力驱动功率模型比电枢速度预测刨削更准确,并提出了预防刨削的建议。     

电磁发射装置电枢轨道配伍性研究

为对电磁轨道发射过程中电枢轨道配伍性进行研究,建立电枢轨道有限元配伍模型,将刨削现象等效为斜冲击动力学问题,分析材料特性、几何形状等因素对刨削行为的影响规律。计算结果表明:增加轨道材料的屈服强度、降低电枢材料的屈服强度和平面电枢轨道配合形状能够减小导轨塑性应变以及塑性区面积,抑制刨削现象的产生。     

超高速面铣淬硬钢涂层刀具切削性能研究

为探索超高速切削条件下涂层硬质合金刀具的切削性能,进行了超高速面铣淬硬钢实验,研究了切屑成形、切削力、刀具磨损以及表面粗糙度的特点。研究结果表明:在切削速度为2 800 m/min时,部分切屑出现了锯齿分离的现象;而在切削速度为2 000 m/min时,开始出现球状切屑;这两种切屑形态分别表征了超高速切削条件下高强度的热、机械冲击以及极高的切削温度;切削力及工件表面粗糙度均随切削速度的升高呈先下降后上升的趋势,并在切削速度为1 500m/min时达到最小值;超高速切削条件下,极高的切削温度导致刀具材料力学性能下降,刀具后刀面的主要失效机理为磨粒磨损、黏结磨损和氧化磨损。由于高强度的热、机械冲击,刀具前刀面的主要失效机理为涂层剥落。     

含能材料防护屏在球形弹丸超高速撞击下的穿孔特性研究

以空间碎片防护设计为工程应用背景,将亚稳态含能材料应用于空间碎片防护结构。利用二级轻气炮对聚四氟乙烯/铝（PTFE/Al）含能材料防护结构进行了不同面密度、不同弹丸直径、不同速度的超高速撞击实验,获得了撞击过程中的高速摄像图片及光学高温计信号。分析结果表明,含能材料防护屏超高速撞击瞬间发生了可靠的冲击起爆反应,根据反应度的不同可分为冲击爆轰区、破碎爆燃区、零反应破碎区3个区域。基于实验结果,建立了铝合金弹丸超高速撞击PTFE/Al含能材料防护屏穿孔直径的无量纲经验公式。利用实验与分析结果验证了数值模拟的有效性,获得了环境温度对PTFE/Al含能材料防护屏超高速撞击穿孔特性的影响规律。     

超高速碰撞材料毁伤效应研究进展

超高速动能武器的快速发展,使武器弹药的打击效能大幅提高,超高速碰撞毁伤效应研究已成为武器弹药研制和目标防护的研究重点。对国内外混凝土、岩石、金属和复合材料的超高速碰撞毁伤效应研究现状进行概述,分析了超高速动能武器的发展趋势,对超高速碰撞毁伤效应研究中存在的问题进行总结,在此基础上,探讨了超高速碰撞毁伤效应未来的研究重点。     

高能量冲击加载试验装置研究进展

轻气炮和空气炮是常见的实验室条件下模拟高冲击、高过载试验环境的加载装置。它们是通过发射弹丸与目标靶件产生撞击，达到冲击载荷加载的要求。轻气炮是研究高速、超高速碰撞终点效应以及含能材料冲击特性的重要模拟加载实验手段。空气炮在研究高g值加速度传感器，振动冲击传感器的动态、静态特性的标定校准，以及侵彻引信部件和器件的高冲击、大脉宽、高能量冲击加载方面有重要应用；空气炮较霍普金森杆装置的冲击加载脉宽大很多。深入系统地分析了国内外相关单位常温条件和高低温环境条件下的轻气炮、空气炮冲击加载试验装置研究现状，并给出了重点发展方向的思考及建议。     

冲击载荷下轨道炮刨削形成机理及仿真分析

针对电磁轨道炮的发射特点,提出了微凸体引起的刨削形成机理;根据实际轨道炮的结构和载荷特点,利用ABAQUS有限元软件在不同的参数条件下进行了仿真计算;发现刨槽的尺寸主要取决于枢轨间相对滑动速度和电枢长度,滑动速度越高刨槽就越宽,而且刨槽尺寸随着电枢长度的加长而变长,但是枢轨界面载荷对刨槽尺寸的影响不大;轨道刨削形成机理的提出及仿真计算,为电磁轨道炮的抗刨削技术研究提供了参考和指导。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

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.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

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.     

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.