纤维增强铝层压板复合材料(FRALL)的弹道冲击贯穿

介绍了对纤维增强铝层压板在Φ９５６ 钢球弹道冲击下贯穿坏的实验研究结果,对其破坏现象、破坏机理以及在不同纤维增强情况下的抗弹性能进行了比较、分析．     

用于飞行器的新型纤维增强金属层压板1──基本情况和一般力学性能

在航空工业中，飞机设计中大部分都选用铝合金，而铝合金现在正面临着纤维增强聚合物（ＦＲＰ）和近年来发展的纤维增强金属层压板（ＦＲＭＬ）的挑战。这些新材料的质量轻、强度高，因此试图将金属和复合材料两者的优点结合起来，纤维增强金属层压板就是由纤维粘合剂预浸和铝合金薄板粘结而发展起来的。讨论了ＲＲＭＬ的发展，叙述了市场上可买到的不同类型的ＦＲＭＬ。对ＦＲＭＬ的性能进行评价，特别是层压板的疲劳性能和缺口强度，主要讨论了聚酰胺层压板，但也谈到了玻璃和碳纤维基层压板，它们都优于聚酰胺基层压板。也讨论为模拟疲劳性能和剩余强度而推荐的模型。最后，根据以上讨论结果，推荐未来的研究领域。     

纤维增强复合材料抗弹吸能特性研究

为研究树脂基纤维增强复合材料的抗弹吸能特性和机制,采用4.5 g球形碎片模拟弹,对不同基体的玻璃纤维和芳纶纤维增强复合材料板进行了弹道极限V50和抗冲击贯穿试验,分析了不同冲击状态下各复合材料靶板的吸能特性和破坏特点.研究发现,增强纤维的应变率效应会显著地反映到复合材料板的抗弹吸能特性中,破坏模式决定复合材料板的抗弹吸能能力;弹体冲击入射速度、纤维与基体的界面特性是影响复合材料板抗弹吸能的重要因素.结果表明,在一定速度下的贯穿比吸能试验方法,可有效地评价和比较各树脂基纤维增强复合材料板的抗弹性能,该试验方法是对V50试验方法的有效补充.     

层合纤维增强复合材料的抗弹性能数值计算研究

以2层Kevlar／Epoxy构成的纤维增强复合材料为例，利用非线性经典层合理论，研究了子层的材料铺层方向对抗弹性能的影响以及复合材料对不同冲击速度的能量吸收，从而得到层合纤维增强复合材料的抗弹特性，得出纤维增强复合板适合于较低速度的冲击防护．     

纤维增强复合材料的断裂力学研究进展

本文对近二十年来国内外研究纤维增强复合材料断裂力学的情况进行了回顾,讨论了复合材料断裂力学的理论发展和目前比较通用的一些断裂判据和各种计算模型,探讨了纤维增强复合材料断裂机制,并对纤维增强复合材料的发展方向表述了己见。     

芳纶复合材料对球形弹丸的抗贯穿性能研究

以芳纶纤维织物为增强材料、聚氨酯为树脂基体的芳纶复合材料,进行了2.05 g钨合金球、1.03 g钢球和4.50 g钢球的抗贯穿性能研究,并分析了芳纶复合材料对以上3种典型球形弹丸的抗弹性能差异。试验结果表明:芳纶复合材料的抗贯穿性能与测试过程中采用的弹丸种类有关,采用2.05 g钨球时较低,采用1.03 g钢球时较高,采用4.50 g钢球时居中。进而提出了一种新的芳纶复合材料抗贯穿性能表征方法,即直接作用面积比吸收能(PSEA)法。PSEA值在芳纶复合材料受到材质相同的球形弹丸冲击时基本相同,据此在芳纶复合材料对某种球形弹丸的弹道极限速度已知时,可计算出对其它球形弹丸的弹道极限速度。验证结果表明:弹道极限速度的计算值和实测值相差1%~6%.     

湿气在层压复合材料内的三维扩散

本文提出一种用于研究层压纤维增强复合材料中吸湿的三维扩散的数学方法。对一种具有实际意义的特殊情况,给出了对应短时间扩散和长时间扩散的解。用三维解得出的数字结果,与采用有效扩散系数来考虑沿边吸湿的近似一维解作了对比。对比表明,对于有实用意义的许多种试样几何形状而言,一维近似能用来预测总增重随时间的变化关系。由石墨/环氧层压板获得的实验数据与由扩散理论得出的数字结果之间也表明有很好的相关性。同时还讨论了层压板边缘近处的湿度梯度对加速环境调节法的影响。     

碳纤维增强复合材料准静态电弧损伤的电-热耦合分析

为有效预测碳纤维增强复合材料(carbon fibre reinforced polymer,CFRP)层压板的雷击电弧附着响应,并探讨阳极试件材料对雷电电弧参数空间分布的影响,基于商业有限元分析软件ABAQUS,分析了CFRP层压板雷电流注入后的热-电-结构耦合,建立了CFRP层压板电弧附着损伤的三维有限元模型。模拟了复合材料层压板在雷电流作用下的冲击响应,进行了复合材料层压板雷击附着机理和作用模式的分析,并探讨了试件尺寸对电弧附着响应特性的影响。研究结果表明,当CFRP试件的长宽比接近1时,CFRP损伤区域往往集中在准静态电弧附着处,与其他长宽比相比,损伤面积较小,但损伤深度较深。     

多层编织预成形件的制造

本文评述了当前通用的三向编织工艺程序,并讨论了为编织三向多层织物由北卡罗纳州大学的火星任务研究中心发展的工艺方法。从简单的层压板到T形截面和Ⅰ形截面的型梁以及大的刚性层压板,织体的体积和复杂性都可以变化。还讨论了诸如纤维走向、每一方向上所需纤维的容积百分数、纱距或密度等决定复合材料物理性能的参数。     

纤维增强环氧复合材料低温性能研究

纤维增强环氧树脂基复合材料因其低温下比强度比模量高、热导率低的特点在低温领域被广泛应用,重点对碳纤维、玻璃纤维、凯夫拉纤维增强环氧复合材料低温下力学及导热性能的研究进行了总结,并对4K、77K及室温下各类单向纤维增强环氧复合材料的力学及导热性能进行了对比,分析了各温度范围内最适用的纤维增强环氧复合材料,指出了当前对纤维增强环氧复合材料低温下力学及导热性能研究的不足之处。     

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.