电阻点焊区的冲击破坏机理研究

利用一级气体炮对QP980高强钢板点焊搭接结构进行一系列点焊区弹道撞击实验。使用全光纤激光多普勒测速仪DISAR-I-35记录电阻点焊区相应位置在撞击过程中的自由面速度历史;通过回收试件,观测不同撞击速度下点焊搭接结构的变形和破坏情况;通过显微维氏硬度测量观察到了焊接热软化区的存在。对实验结果的分析表明,点焊区的冲击破坏特性受搭接边界和焊接热软化区影响。     

高速破片撞击飞机油箱的数值模拟研究

为研究飞机油箱在水锤作用下的破坏效应,运用数值计算方法对高速破片撞击充水箱体的破坏响应进行研究。采用赋予破片速度和ALE建模的方法数值模拟高速破片撞击充水箱体的破坏响应,并对不同破片速度和不同充水比下箱体的变形进行比较分析。计算结果表明:破片撞击充水箱体时的破坏效应较空箱体要严重得多,箱体前后壁的穿孔处周围是发生破坏最严重的区域;箱体前后壁的变形量随破片速度的增加而增加;部分充水箱体的变形明显小于完全充水的情况,但对于充水75%和85%的箱体变形差距不大。     

防空导弹威胁下的飞机金属结构损伤研究

为了研究战斗部高速破片对飞机金属结构的破坏机理,计算了冲击压力和温度。为了研究热辐射的破坏机理,开展了烧伤试验。研究表明,高速破片撞击下飞机金属结构将产生很高的压力和温度;金属材料烧伤后其强度下降,而硬度的变化则因材料而异。综合分析表明:防空导弹对飞机金属结构损伤模式主要表现为高速破片撞击下的破孔损伤、热辐射作用下的材料性能改变以及冲击波作用下的局部变形和撕裂破坏。     

高聚物粘结炸药Steven试验低速撞击破坏和点火的数值模拟

建立了Steven撞击试验有限元计算模型。采用热力耦合模型和Arrhenius方程描述炸药的热反应,用节点分离方法模拟炸药的破坏,对不同形状弹头低速撞击高聚物粘结炸药的响应过程进行了数值模拟研究。计算得到的破坏模式、点火区域和点火阀值速度与试验结果吻合较好。分析了弹头形状对炸药受力和反应的影响。计算结果表明,弹头形状会影响炸药的受力,从而导致炸药的点火阀值速度和点火位置的不同。     

TATB基PBX及其与HNS复合装药的高速破片撞击安全性

为了获得高速破片撞击下钝感装药的安全性响应规律及传爆药非理想起爆对该过程的影响,采用高速破片撞击试验方法,对TATB基PBX装药(PBX-C04)和PBX-C04/HNS复合装药结构进行了试验研究.基于超压测试、鉴证板破坏情况和残药的理化分析,分析了撞击速度、传爆药非理想起爆及高温对PBX-C04钝感主装药高速破片撞击安全性的影响.结果表明,常温下PBX-C04主装药具有优异的高速撞击安全性,1970 m·s-1的高速破片撞击下仅发生燃烧反应,引入六硝基茋(HNS)传爆药后,相同撞击速度下PBX-C04主装药反应烈度提高为爆燃反应.复合装药结构加热至200℃时,1640 m·s-1撞击速度下,复合装药结构发生了爆轰反应,证明高温可急剧恶化复合装药结构的高速撞击安全性.     

层叠顺序对UHMWPE-铝合金板抗冲击性能影响

为探究层叠顺序对双硬度UHMWPE-铝合金板抗冲击性能影响,以高分子聚乙烯(UHMWPE)板、7075高强铝合金板为对象,利用一级轻气炮开展一系列平头和卵形弹打靶试验,对靶板弹道极限速度、能量吸收率、破坏模式等进行分析.揭示板材层叠顺序对接触式高分子聚乙烯-铝合金靶板防护性能的影响规律.结果表明:平头弹撞击下,UHMWPE板在前铝合金板在后的叠放顺序("软+硬")防护性能更高;卵形弹撞击下,两种叠放顺序靶板防护性能相近;两种叠放顺序靶板在平头弹撞击下均发生"冲塞破坏",在卵形弹冲击下均发生"延性扩孔"破坏.     

不同弹形撞击下泡沫铝夹芯结构动力学性能研究

为研究不同弹形撞击下泡沫铝夹芯结构的动力学性能,通过空气炮发射方式分别开展了球形弹、锥头弹和平头弹撞击泡沫铝夹芯板试验。基于非线性动力有限元软件LS-DYNA进行了不同弹形撞击泡沫铝夹芯板的数值仿真,分析了不同弹形、不同速度对夹芯板吸能特性的影响。试验结果与仿真结果一致性较好,结果表明：锥头弹撞击变形模式与球头弹撞击变形模式基本相同,平头弹侵彻过程中产生较严重的冲塞破坏,前面板和后面板呈现撕裂破坏模式,侵彻后夹芯被压实部分泡沫铝粘接在后面板上;锥形弹头部尖锐,弹头与靶的接触区域小、侵彻力大,平头弹的弹头和靶的接触区域大、侵彻力小,但靶面破坏区域大且撞击后效更大,球头弹则居于二者之间;当速度较低时,改善前面板和夹芯板的厚度以及材料性能可以较好地提升泡沫铝夹芯板的性能;当速度较高时,后面板吸能比例逐渐增大,重点改善后面板的厚度和材料性能可以较好地改善夹芯板抗侵彻性能。     

硬回收装置的设计探讨

文中给出了硬回收装置在高速撞击条件下的几种破坏模式,结合这些破坏模式产生机理就硬回收装置的材料选择、结构形式、结构形状和缓冲等方面设计要点进行了详细阐述.     

炸药冲塞点火的数值模拟

为研究和评价炸药在机械撞击作用下的安全性,采用节点约束-分离的数值计算方法,联合热弹塑性材料本构方程和化学动力学方程,对PBX-2炸药的冲塞点火过程进行了数值模拟。探讨了网格尺寸对炸药冲塞温升的影响,获得了炸药冲塞过程中的力学破坏物理图像和局部温度时间曲线,计算得到了PBX-2炸药冲塞点火的临界跌落撞击速度。结果与实验值吻合较好,表明该方法可以有效地描述炸药冲塞破坏和热-力-化耦合作用下的点火反应。     

缸套振动及其对缸套穴蚀的影响

振动是缸套穴蚀的主要因素,本文用有限元法对活塞撞击缸套引起的缸套振进行了模拟计算,并论述了对缸套穴蚀的影响,以此得出结论,12V180ZL 型柴油机缸套的穴蚀破坏程度主要决定于缸套振动强度.     

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.     

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.     

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.     

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.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.