固体推进剂黏弹性参数的确定及细观损伤演化

固体推进剂力学模型参数的准确性对其宏观力学响应预测具有重要的意义,为解耦标定固体推进剂非线性黏弹性模型参数,提出一种基于台阶应力松弛试验的模型参数确定方法。通过台阶应力松弛平衡响应确定固体推进剂弹性部分参数,通过小变形下的应力松弛确定无量纲松弛模量,分析一种固体推进剂力学响应。研究结果表明：固体推进剂在台阶应力松弛及单轴拉伸条件下的力学性能预测结果与试验结果吻合,验证了所提方法的有效性;由于平衡响应包含损伤,采用该方法标定的参数可用于预测含损伤固体推进剂力学响应。在此基础上,提出一种基于推进剂模型参数标定等效黏合剂力学参数的方法,并通过引入基于黏弹性脱湿准则的相界面模型建立代表性体积单元计算模型,实现在宽应变(～100%)范围内推进剂脱湿损伤分析,为推进剂宏观力学性能预测及细观损伤演化分析提供了支撑。     

低温动态加载下三组元HTPB复合固体推进剂的失效判据

基于三组元端羟基聚丁二烯(HTPB)复合固体推进剂在不同热加速老化时间(0,32,74,98 d)和不同加载温度(-50,-40,-30,-20,25℃)以及不同应变率(0.40,4.00,14.29,42.86,63 s~(-1))条件下的单轴和准双轴拉伸力学性能实验以及细观损伤观测实验,分析了加载条件对推进剂初始弹性模量,强度和最大伸长率的影响规律,确定了单轴和准双轴拉伸加载下推进剂的失效判据。结果表明:动态单轴加载下推进剂易因拉伸应力作用而失效,且热老化后推进剂抵抗破坏的能力降低,拉伸时的最大伸长率可选为失效判据。其次,拉压强度比更能反映推进剂的动态单轴拉压差异性,室温和低温条件下,其数值分别接近于0.4和0.2～0.3。动态准双轴拉伸加载下,推进剂的最大伸长率较单轴加载时明显降低,降低的幅度随热老化时间增长而增大,且温度越低,降低越明显。未老化推进剂在准双轴拉伸加载下的最大伸长率约为单轴拉伸条件下数值的60%～85%,而老化后约为40%～60%。低温高应变率条件下,最大伸长率不受应力状态和应变率变化的影响。动态双轴拉伸条件下的最大伸长率可选为相应加载下推进剂的失效判据以及点火建压条件下战术导弹固体火箭发动机(SRM)药柱结构完整性分析的判据,其数值可结合主曲线和老化模型确定。     

考虑初始缺陷的HTPB推进剂粘超弹本构模型

为研究端羟基聚丁二烯(HTPB)推进剂存在初始缺陷对其宏观力学性能的影响,对定制的不同界面缺陷含量的HTPB推进剂开展了多步松弛和单轴拉伸试验。获得了HTPB推进剂的平衡响应曲线和拉伸曲线。采用Ogden模型拟合了不含缺陷的HTPB推进剂的平衡响应曲线,引入应变率参数M来描述HTPB推进剂单轴拉伸曲线的率相关特性。通过该曲线拟合,得到了不含缺陷的HTPB推进剂的粘超弹本构模型参数。考虑了缺陷的影响,通过引入初始缺陷损伤因子f,构建了含初始界面缺陷的HTPB推进剂的粘超弹本构模型,分步拟合得到了所有模型参数。最后,用本研究所建模型预测了单轴拉伸载荷下的HTPB推进剂的宏观力学性能,结果表明,预测结果与试验结果一致,二者最大偏差仅为4.4%,验证了模型的可靠性。     

单轴拉伸下NEPE固体推进剂细观结构演化行为研究

为了分析硝酸酯增塑聚醚（Nitrate Ester Plasticized Polyether, NEPE）推进剂在单轴准静态拉伸载荷下细观结构演化行为,基于Micro-CT对拉伸过程中NEPE推进剂开展了原位观测试验,对NEPE推进剂中高氯酸铵（AP）颗粒和初始缺陷的尺寸、形状等细观结构特征进行了表征,获取了单轴拉伸过程中推进剂细观结构的失效过程,并采用孔隙率对NEPE推进剂细观损伤的变化规律进行了定量分析,基于NEPE推进剂细观尺度上结构的演变规律解释了宏观力学性能变化的原因。结果表明,NEPE推进剂初始缺陷尺寸小、体积占比低,平均值为0.12%。单轴准静态拉伸过程中,NEPE推进剂的细观失效过程主要包括孔洞形核、生长与汇聚3个阶段;AP颗粒的体积分数虽然低,但是由于容易脱湿通常成为细观损伤的起点;当AP发生一定程度脱湿后,奥克托今（HMX）也会出现明显的脱湿,在分析NEPE推进剂细观失效问题时应当考虑HMX脱湿行为的影响。大量细观缺陷的形核与生长是NEPE推进剂宏观力学性能进入非线性段的原因,而细观缺陷的不断汇聚使得宏观应力增加落后于应变增加的现象越来越明显。加载过程中孔隙率呈现出先缓慢增加再急剧增加最后增加趋于平缓的变化趋势,孔隙率的变化规律不仅能够定量地反映NEPE推进剂细观缺陷的演化阶段,与NEPE推进剂宏观力学性能的变化也具有一定的对应关系。     

丁羟四组元推进剂的宽温围压单向拉伸力学行为

为了研究丁羟四组元推进剂在宽温围压条件下的单向拉伸力学性能，采用宽温-围压气体试验系统研究了不同温度（-50 ℃、20 ℃和70 ℃）、不同围压（0.1 MPa、2 MPa与8 MPa）与不同拉伸速率（100 mm·min^-1、1000 mm·min^-1和4200 mm·min^-1）下推进剂力学性能的变化规律。采用SEM扫描电镜与微米CT相结合的手段从细观层面分析宏观力学性能发展的内在细观原因，以此揭示外载荷对高固含量推进剂力学性能的影响机制。研究表明，常温与高温条件下，推进剂的损伤以“脱湿”为主；低温常压下则主要为“脱湿”和颗粒的韧断，当围压增大时会向颗粒的脆断转变，但延伸率随围压的增大仍然增大，分析认为主要是围压抑制了孔洞的产生和损伤的演化；在高围压不同拉伸速率下，常温和高温下推进剂表现出来的力学性能较为接近，这是因为高温会使粘合剂基体与固体填料之间的相互作用减弱，推进剂出现更严重的脱湿，而高围压则会抑制“脱湿”而减弱温度的影响；采用时压等效叠加原理（TPSP）进行最大抗拉强度主曲线拟合分析时，在低温-50 ℃条件下，时间-压强压位移因子与对应围压之间的关系并不符合标准形式，对于高固含量的推进剂而言TPSP叠加原理具有一定的使用局限性。     

HTPB推进剂温度相关性失效准则

为建立考虑温度及应变率效应的端羟基聚丁二烯(HTPB)推进剂失效准则,通过不同温度下的HTPB推进剂应力松弛实验(233.15,253.15,273.15,293.15,323.15,343.15 K)得到了HTPB推进剂的时温等效因子,基于累积损伤理论和线性粘弹性理论,建立了含时温等效因子αT的推进剂失效准则,结合不同温度、不同速率下的单轴拉伸实验数据获取了失效准则损伤参数。利用该失效准则预测了不同温度和拉伸速度下推进剂材料的损伤演化特性和临界失效时间,与实验结果对比分析发现,失效准则预测相对误差低于20%,表明该失效准则能在低温233.15~273.15 K,拉伸速度2~500 mm·min~(-1)和高温293.15~343.15 K,拉伸速度0.5~100 mm·min~(-1)的条件下预测HTPB推进剂的失效情况。     

温度对HTPB推进剂疲劳特性的影响

为了研究端羟基聚丁二烯(HTPB)推进剂不同温度下的疲劳特性,进行了不同温度下恒应力控制的疲劳循环加载试验。以峰值应变作为损伤因子,基于损伤力学和粘弹性理论,建立了HTPB推进剂含温度效应的疲劳损伤三阶段演化模型。结果表明,随着温度的升高,材料的疲劳寿命缩短,疲劳断裂应变增大。疲劳过程中的峰值应变具有明显的三阶段演化规律:初始变形阶段、稳定发展阶段和加速阶段。建立的三阶段演化模型克服了两阶段模型不能考虑宏观裂纹扩展的缺点。拟合模型参数,运用线性回归的方式预测了213 K和333 K的理论结果,该结果和试验结果较为一致,因此,它可以很好地表征材料的损伤演化规律。     

基于能量耗散率的NEPE推进剂疲劳损伤分析

为研究NEPE推进剂在应变加载条件下的疲劳损伤演化,基于循环加载过程中的推进剂耗散能变化,利用能量耗散变化比对推进剂疲劳过程进行分析。通过4个应变幅值进行了单轴拉伸疲劳试验,得到不同应变幅值下NEPE推进剂疲劳寿命,并得到在不同加载周次下的耗散能。结果表明,这种能量法能够以直观的方式解释疲劳损伤过程中损伤的累计,在对数坐标下耗散能变化比的稳定值与疲劳寿命呈明显的线性关系,稳定值随初始加载应变幅值的增大而增加。当加载应变增大时,材料稳定段相邻加载间损伤累计越快,疲劳寿命相对减小,也解释了2次循环加载间损伤发展的原理。     

宽温域宽应变率下丁羟四组元HTPB推进剂单轴压缩力学行为

为研究丁羟四组元端羟基聚丁二烯（HTPB）推进剂在宽温域宽应变率下的单轴压缩力学行为,基于万能材料试验机、高速液压伺服试验机、分离式霍普金森压杆,结合可程式恒温恒湿试验机等温控手段,开展了宽温域宽应变率下的推进剂单轴压缩力学性能实验,获取了-40,-25,-10,20,50 ℃ 5个温度下10^-4~10³ s^-1应变率的丁羟四组元HTPB推进剂的应力应变曲线,并建立了HTPB推进剂的分段式单轴压缩率温本构关系。结果表明,HTPB推进剂的力学响应存在显著的率温相关性,在任意应变率下其力学响应都呈阶段性变化,即线弹性阶段-非线性屈服阶段-应变软化阶段或应变硬化阶段;且在高应变率下,非线性屈服行为后的应变软化现象明显弱于低、中应变率。此外,高应变率时,随着温度的降低,应力应变曲线的变化速率逐渐减缓;而低、中应变率却恰恰相反,随着温度的降低,应力应变曲线的变化速率逐渐加快。HTPB推进剂的力学强度随着温度的降低显著增大,温度从50 ℃降低至-40 ℃时,HTPB推进剂试件在宽应变率作用下的最大应力从2.2~8.8 MPa增长至约11~22 MPa。同时基于实验数据构建了分段式率温本构关系,发现其在温度较高时拟合效果更好,能够较好地预测HTPB推进剂的力学行为。     

HTPB/IPDI复合固体推进剂细观界面率相关参数的反演识别研究

为研究HTPB/IPDI(hydroxyl-terminated polybutadiene/isophorone diisocyanate)复合固体推进剂细观界面性能随加载速率的变化规律,基于分子动力学算法生成了HTPB/IPDI复合固体推进剂的细观颗粒填充模型。颗粒与基体间粘接作用通过结合粘弹性标准机械单元及指数型率无关内聚本构所构建出的率相关内聚力模型模拟。通过HTPB/IPDI基体胶片的应力松弛试验得到细观模型中基体材料的松弛参数。基于模型对HTPB/IPDI推进剂在不同加载速率下(0.1,5,20 mm·min~(-1))的宏观力学响应进行仿真计算。利用数值仿真结果与HTPB/IPDI推进剂单轴拉伸试验结果曲线,通过Hooke-Jeeves优化算法对率相关内聚力模型参数进行反演分析,得到了优化后的界面参数数值。利用所建立的模型对50,100 mm·min~(-1)加载速率下的HTPB/IPDI复合固体推进剂材料的宏观力学行为进行预测。结果显示,预测结果与实际试验结果较为一致。     

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.