火箭弹撞盖力数值仿真及实验研究

储运发箱式火箭炮前密封盖设计是该类火箭炮关键技术难题之一。由于该类火箭炮结构特性所决定,实弹射击时火箭弹撞击密封盖过程中的撞击力无法实验测试,因此应用LS-DYNA的显式中心差分算法,对某储运发箱式火箭炮撞盖力进行了数值仿真分析和模拟实验测试研究,解决了该火箭炮实弹射击时无法实测火箭弹撞击前密封盖瞬态响应的难题。对数值仿真与模拟实验测试的撞盖力结果进行了对比,其结果相对误差小于12%,仿真结果对解决该类火箭炮关键技术难题——密封盖合理设计提供了正确的理论依据。依据仿真结果改进后的前密封盖经实弹射击试验验证,完全达到了技术指标要求。     

燃气压力保险机构在火箭弹引信中的应用

对于火箭弹引信，在设计时选取可利用的环境相当困难，尤其是低旋的火箭弹时间引信。将火箭发动机燃气压力的变化特征作为火箭弹特有的飞行环境，可为这类火箭弹引信的设计提供可靠的依据。火箭发动机正常点火后，火箭发动机燃气压力会经历一个骤升、持续和骤降的过程。分析了火箭发动机燃气压力骤升、持续和骤降的表现特征，并详细地介绍了利用这些特征工作的燃气压力保险机构及其常有的结构形式，对这些机构的工作特征进行了具体的安全性分析和比较，在此基础上根据实践经验对于设计中应注意的密封环节提供了具体的技术方案，结合试验验证，提出了廉价有效的隔热措施。     

读者之声

广东佛山读者杨雨来信问: 多管火箭炮是按怎样的顺序发射火箭弹的? 在讲多管火箭炮的发射顺序之前,让我们先谈一下发射火箭弹时火箭弹对火箭发射架的燃气流冲击作用力。火箭弹是一种靠其自身的     

2枚火箭同时发射时火箭炮动态特性分析

针对某轮式多管火箭炮,采用动力学仿真的方法对2枚火箭同时发射时火箭炮动态特性进行了研究,得到了基于燃气射流分析、发射动力学仿真和火箭初始扰动计算的火箭炮动态特性数据,结果表明2枚火箭同时发射能保证该火箭炮的安全性,有利于提高火箭射击密集度,为火箭炮2枚火箭同时对称发射提供了理论依据.     

对某型多管火箭武器减少试验用弹量的仿真

采用系统仿真技术对某型多管火箭武器系统减少试验用弹量进行研究,首先给出确定1组非满管用弹量的方法,然后对满管和非满管情况分别建立以下模型进行仿真计算：建立燃气流模型,计算燃气射流冲击发射装置迎气正面的作用力和作用力矩;建立发射动力学模型,对发射过程建模和分析,得到炮口起始扰动的角位移和角速率;建立外弹道模型,即在发射动力学得到的火箭炮炮口参量下,进行火箭弹炮口扰动的转化,进而进行射击密集度的计算。最后进行置信度检验。仿真结果表明,将1组齐射40发减少到1组齐射12发,密集度指标无显著性差异。     

某多管火箭炮发射动力学模型(Ⅰ)

多管火箭炮发射是一个复杂的动力学过程,把它简化为由车体、回转机、起落部分和火箭弹组成的力学系统,采用多体动力学模型,在半约束期,系统简化为11个自由度,在全约束期,系统简化为9个自由度.运用速度矩阵法推导了火箭弹与火箭炮运动相耦合的动力学方程.提出了燃气射流冲击力在迎气面上的积分算法,为分析计算火箭弹离轨时刻的空间姿态和发射架振动提供了理论模型.     

引信头锥摆动角对火箭弹气动特性及控制能力影响

针对低旋火箭弹在引信头锥摆动时改变了全弹的气动特性问题,进行了气动特性仿真,分析了引信头锥摆动角对火箭弹气动参数的影响,并利用气动仿真得到的数据进行控制能力的仿真,从而为弹道修正火箭弹设计提供依据。仿真结果表明:升力系数和俯仰力矩系数随引信头锥摆动角的增大都有显著的增大,且在稳定飞行时引信头锥摆动火箭弹的修正能力可以满足火箭弹二维弹道修正的要求。     

某多管火箭炮发射动力学模型(Ⅱ)

上一篇提出了基本假设条件,建立了坐标系和动力学方程组,分析了火箭弹推力和燃气射流冲击力.多管火箭炮发射时受力复杂,除火箭弹推力和燃气射流冲击力外,还有火箭弹闭锁力、定向钮与导向槽的正压力和摩擦力、前后定心部与定向器的正压力和摩擦力、回转机力,高低机力、车轮悬挂和千斤顶的力、重力等.将这些力转化为广义力供分析计算.叙述了起落部分质量和转动惯量在发射过程中不断改变的状况,给出了因火箭弹逐一发射而变化的算法,为分析计算火箭弹离轨时刻的空间姿态和发射架振动提供了理论模型.     

某火箭炮易碎盖瞬态动力学与实验研究

以某多管火箭炮贮运箱易碎盖为对象,建立了火箭弹和易碎盖两种材料的有限元模型,利用ANSYS/LS-DYNA软件进行瞬态动力学分析,计算了火箭弹碰撞易碎盖的全过程,得到了引信的应力应变以及易碎盖碎片速度、位移曲线.数值计算结果与实验数据对比,取得良好的一致性,研究表明,该方法为实弹射击试验研究提供一定的理论依据.     

火箭弹引信炮口撞击安全前冲保险机构

为了解决火箭弹引信在主动段内碰障碍物发火的"撞击安全性"问题,在不影响火箭弹引信总体结构设计的条件下,设计了一种炮口撞击安全前冲保险机构.火箭弹引信在主动段内碰障碍物时,该机构中的保险销迅速前冲,进入转子上的空缺,阻止转子在前冲力矩作用下转正而使引信解除保险.仿真计算和靶场试验验证了本设计的正确性和作用可靠性.     

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.     

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。     

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.