药柱等静压实验和数值模拟计算

 进行了炸药柱等静压实验，用热电偶测量了药柱压制成型过程中的内部温度，建立了药柱在等静压下的热力耦合模型。对炸药柱保压阶段进行了数值模拟计算，得到等静压条件下药柱内部压力和温度变化，分析了药柱形变，压力和温度分布。结果表明：在等静压下药柱各表面均有明显的向里凹陷的现象，在受力过程中炸药内部温度升高，并存在温差，内部压力分布不均匀。     

JB-9014等静压成型件的力学及热性能

炸药件的等静压成型工艺作为一种较新的压装成型装药技术，由于在压制过程中受力均匀、颗粒的空间排列也较为紧凑合理，因此成型的炸药件整体密度高、密度均匀性好、各种热性能及力学性能可以保持较好的各向同性且性能较好。     

等静压、模压JOB-9003炸药件力学性能各向同异性

高聚物黏结炸药部件是通过不同成型工艺将造型粉压制成形再加工而成的。炸药的压制成形已有模压、半软半硬等静压到全软模等静压等不同成型工艺。在使用这些炸药部件以及对这些炸药部件进行力学性能分析时，一般均假定其力学性能是各向同性的，但尚未进行过试验研究。本文在这些不同工艺成形的JOB-9003炸药部件上取样测试，以不同方向取样的拉伸和压缩强度随温度变化曲线之间的差异比较不同工艺间力学性能的各向同异性，不同取样方向的拉伸和压缩强度随温度变化曲线如图1-2所示。     

粉末高速压制成形过程中的应力波分析

应用离散单元法,模拟了粉末高速压制成形过程中的压力传播过程.根据粉末高速压制成形的工艺特性,把一次压制过程分为弹性加载、塑性变形、弹性卸载三个阶段;基于离散单元法的基本理论,分别建立了三个阶段的控制方程;应用PFC2D软件对粉末高速压制过程模腔内部颗粒的运动状态进行了数值模拟,给出了压坯内部的压力分布,得出了实验中无法测量的压坯内部应力传播波形.数值模拟结果显示,压力作用曲线表现出明显的弛豫现象,形成了倾斜度不同的锯齿状加载波形和卸载波形,压坯底层的应力波与实验得到的应力波相符. 关键词： 高速压制成形 离散单元法 接触模型 应力波     

冲击作用下非均质炸药热点形成的离散元方法

用离散元方法模拟以HMX为基的塑料粘结炸药与HMX颗粒炸药在冲击载荷作用下的细观响应过程.结果表明对于HMX颗粒炸药,炸药颗粒界面处的温度及压力远高于颗粒内部;对于HMX为基的塑料粘结炸药,粘结剂处的温度及压力亦高于颗粒内部;两种冲击响应过程的对比分析表明,粘结剂有效地降低了炸药颗粒边界处的温度及压力.     

金属粉末压坯烧结过程的内耗研究

烧结在粉末冶金过程中对最终产品质量起着关键性作用,理解和探索烧结过程中粉末压坯结构和缺陷的演变,明确烧结的起始温度、结晶温度等,可为烧结工艺的确定提供确切的信息.本文采用内耗技术系统研究了单元系纯Al, Mg, Cu, Fe粉末压坯烧结过程的内耗行为.在第一个循环的升降温过程中各发现了一个内耗峰、升温峰和降温峰.降温峰是一个稳定的弛豫型内耗峰,激活能和峰温表明,该峰起源于晶界的黏滞性滑移.升温峰的出现伴随着相对动力学模量和电阻的下降,材料性能发生显著变化,相应峰温可考虑作为单元系粉末烧结的起始温度.升温峰具有明显的压坯颗粒粒径和成型压力依赖性,随颗粒粒径或压制压力的减小而升高,这与颗粒间弱结合界面数量和微滑移可动性的增大有关.在升温测量时,主要通过弱结合界面微滑移耗能,内耗增加直至峰温所在位置,弱结合界面转化为颗粒间晶界,内耗迅速下降,形成了非稳定升温峰.升温峰的出现表明了粉末压坯烧结过程中颗粒间晶界的形成,相应峰温亦可作为粉末压坯的结晶温度.     

燃料抛撒成雾及其燃烧爆炸的光滑离散颗粒流体动力学方法数值模拟研究

燃料在炸药爆炸驱动下形成燃料空气爆炸云团, 进而引燃爆炸, 对目标造成毁伤. 本文在前期提出的光滑离散颗粒流体动力学方法(SDPH)的基础上, 引入描述炸药由爆轰到膨胀整个过程的Jones-Wilkins-Lee状态方程及描述气体快速燃烧过程的EBU-Arrhenius燃烧模型, 建立了求解战斗部起爆、燃料抛撒和燃料二次引燃爆炸问题的新型SDPH方法. 设计了圆环形燃料颗粒在炸药爆炸驱动下运动抛撒的算例进行数值验证, 结果与理论相符; 对燃料空气炸药(FAE)云雾的形成和发展过程进行了数值模拟, 分析了云雾的形态, 并与实验结果进行对比, 符合较好, 同时分析了不同起爆方式对云雾团成型的影响; 最后, 在云雾团成型的基础上, 引入蒸发燃烧模型对FAE的燃烧爆炸过程进行了模拟研究. 结果表明, 本文建立的数学模型和计算方法可以较好的模拟燃料空气炸药抛撒成雾及云雾燃烧爆炸过程, 为该类武器装备的设计研究提供了较好的数值方法.     

金属隔层和空气间隙对钝感炸药冲击起爆的影响

为了确定空气间隙和金属隔层对冲击起爆的影响,采用火炮加载蓝宝石飞片冲击起爆Φ50 mm×30 mm的A型炸药,产生的冲击波通过空气间隙和金属隔层起爆Φ50 mm的台阶型B型炸药。在B型炸药的后界面粘贴镀膜氟化锂(LiF)窗口,使用光子多普勒测速仪(PDV)测量金属和B型炸药的后界面速度,进而计算得到金属和B型炸药的冲击波透射压力,再利用阻抗匹配计算得到金属和B型炸药的入射压力。结果表明:传爆药和金属隔层间的空气间隙使冲击压缩过程转变为准等熵压缩和冲击压缩两个过程,同时使冲击波的幅值减小;确定了金属隔层厚度为5 mm时冲击波压力的衰减范围;当使用A型炸药作为传爆药,空气间隙为0.3 mm,金属隔层厚度为5 mm时,B型炸药在7~10 mm之间开始反应。     

重力驱动下运动物体在颗粒介质中的最大穿透深度

通过高速摄像的跟踪，研究了重力场中球形下落物体对松散颗粒床进行撞击并进入颗粒床内的运动过程.运用已得到的颗粒体系中运动物体的阻力模型，分析了物体质量对穿透深度的影响.研究表明，当物体与颗粒床撞击的初始速度较小时，物体在颗粒床中的最大穿透深度与物体质量呈近似线性关系. 实验得到的结果与模型符合很好. 关键词： 颗粒体系 阻力 动力学过程     

循环床中气固两相局部传热传质规律的研究

本文对含湿颗粒在循环床中干燥过程的传热传质规律进行了实验研究。本文发展的一种利用双热电偶参考标定法，获得了气、固两相沿床高的局部温度。对气体表观流速，固体循环率，颗粒初始含湿量对传热传质的影响进行了分析和讨论。所获得的循环床中传热传质系数的实验关联式，可供干燥颗粒、造粒、粒面包裹等工业设计参考使用。     

High strain rate deformation microstructures of stainless steel 316L by cold spraying and explosive powder compaction

Cold spraying is a new coating technique in which dense, tightly bonded coatings form only due to the high kinetic energy of impinging particles of the spray powder. These particles are still in the solid state during impact. Explosive powder compaction is a technique where powder is consolidated by a shock wave. In the shock front the powder is deformed under high strain rates, which under suitable conditions results in high-strength bonding of the particles. Thus, the microstructural features obtained by both techniques should be similar. This study correlates the microstructure of cold-sprayed 316L austenitic steel coatings in comparison to the microstructure of 316L samples obtained by explosive compaction. The results provide insight into the prevailing local deformation mechanisms, as well as into the physical background of observed phase transformations. PACS 81.15.Rs; 61.72.Ff; 62.50.+p; 64.60.My; 64.70.Kb     

爆炸粉末烧结颗粒间摩擦引起的界面温升研究

 针对爆炸粉末烧结过程中颗粒间的摩擦效应提出了一种无夹角斜碰撞模型，分析了烧结过程中颗粒间摩擦力随温度的变化规律，借助于LS-DYNA有限元程序研究了冲击压力、颗粒大小、材料强度等因素对孔隙闭合时间的影响，给出了颗粒界面温升的表达式。研究结果表明，由摩擦引起的颗粒界面的温升与材料特性、颗粒度、冲击角度、冲击压力等因素有关，随材料的蓄热能力、传热能力和材料强度的增加而减小，并随着材料疏松程度、颗粒直径、冲击压力的增加而增加；在粉末颗粒直径和冲击压力不是太小的情况下，颗粒表面温度将达到材料的熔点。     

Acceleration Ability of Aluminum-Containing Explosive Compositions

Results of a study of explosives with varying oxygen balance by a method based on the acceleration of a steel plate from the charge end face (M-40) have confirmed the possibility of increasing the acceleration ability of these substances owing to the addition of powdered aluminum. The experimental and calculated data suggest that, in the case of mixtures prepared by the conventional method of mechanical mixing, compositions with aluminum nanoparticles and compositions containing aluminum with a particle size on the order of a few microns have similar acceleration ability values. Nanocomposites—systems with a uniform distribution of aluminum nanoparticles in the explosive matrix—can be superior to the mechanical mixtures in acceleration ability in the case of a highly negative oxygen balance of the explosive base. Calculations have shown that the acceleration ability of mixtures of low-sensitivity explosives with aluminum can be further increased owing to the formation of nanocomposites.     

超音速侵彻混凝土过程中装药安定性结构设计的动摩擦理论分析

 根据侵彻过程中弹体内部装药的弹性变形假设,利用弹体结构与内部装药的相对位移、摩擦功、热力学原理和热点理论,提出了装药热安定性设计的弹性理论分析方法。计算中,侵彻弹体的响应函数从空穴膨胀理论出发;利用弹塑性材料中应力波Hugoniot跳跃条件以及流体力学动量和质量守恒方程,分析了弹体侵彻混凝土过程中的弹体表面径向应力;结合牛顿第二定律,采用有限差分技术,获得了弹体侵彻过程的轴向阻力。通过弹性理论分析,得到了弹体侵彻过程中影响装药安定性的重要设计参数,为装药安定性设计提供了理论依据。     

The use of explosion in fabrication of new materials

Abstract

The energy of high explosives have been widely used for some time in improving characteristics of the existing materials as well as for creating new materials having good prospects for different technological applications. The two last decades witnessed especially remarkable results in this field. In this paper we shall give a concise review of explosive metal hardening and welding processes, explosive compaction of metalxnon-metal materials as well as of the equipment used in industrial applications of these and some other processes of explosive treatment of materials.     

Macrokinetics of the retention of condensed carbon and detonation diamond in a hermetic explosion chamber

The effect of the thermophysical parameters of a cooling medium on the macrokinetics of secondary physicochemical processes that occur in a hermetic chamber after the explosion of a solid explosive charge is studied. The yields of condensed carbon and the content of the diamond phase in it are mainly determined by the temperature of the medium in the chamber after explosion. The maximum yield of detonation diamond synthesized from a trinitrotoluene-hexogen TG50/50 alloy is equal to ～10% of the initial explosive mass and is achieved when the steady-state temperature of the medium in the chamber does not exceed T_m=550±50 K. As this temperature increases, the yield of detonation diamond decreases approximately in inverse proportion to the temperature, and, at T_m>2800 K, there is virtually no diamond phase in the explosion products. The conversion of condensed carbon due to the presence of the oxygen-containing components of the explosion products (CO₂, H₂O) begins at a temperature of the medium of above 1550±150 K. The decrease in the final energy release that is experimentally detected in calorimetric studies in the case of an explosion of solid explosives with a negative oxygen balance in an inert gaseous medium or in the case where explosives are surrounded by massive shells results from the endothermic conversion of condensed carbon, which absorbs a significant portion of the explosion energy.     

非均匀炸药冲击起爆和起爆后的行为

 介绍并分析了Campbell 等人及其他作者研究非均匀炸药冲击起爆和起爆后行为所获得的实验结果，但不涉及其冲击起爆条件。足够强的冲击波进入非均匀炸药后，爆轰将瞬时（指不经过感应时间）且直接（指不经过其他过程，如爆燃）被引发；非均匀炸药起爆后，其中传播的自始至终是一个不断增长的爆轰波，直至发展为正常爆轰，整个过程都是爆轰的增长（新定义）过程。不存在由反应冲击波不断增长并转变为爆轰波的所谓向爆轰的增长。所谓向爆轰的增长，实际上是爆轰的增长（按新定义）的初期；Craig原定义的爆轰的增长，实际上是爆轰的增长（按新定义）的后期；而所谓反应冲击波，实际上是增长中的初期爆轰波。爆轰的增长（按新定义）是所有猛炸药的特性，炸药反应不充分并逐渐趋于充分是爆轰的增长的化学机制。     

真空环境火炸药辐射强度测试方法

在大气环境中，针对爆炸物辐射强度的测试方法较为成熟。随着高空或外大气层爆炸物研制技术的飞速发展，对该类爆炸物瞬态红外辐射强度的测试要求越来越迫切。由于外太空环境是一种低温、近真空的环境，且无法进行实地测量，所以作者创造性地提出了在实验室中模拟真空环境，从而对火炸药红外辐射强度进行测试，并进一步建立了专用的真空环境和测试方法，对4组特定组分的火炸药，利用专用测试装置进行了测量并分析了测量结果。针对存在的问题，阐述了未来的改进方向。     

Experimental measurement of energy release from an initiating layer in an insensitive explosive

When subjected to a shock of insufficient strength to trigger prompt reaction, heterogenous condensed phase explosives can form regions where significant amounts of the explosive remain unreacted for times much greater than the reaction time of the detonating explosive. This phenomena is observed for the explosive PBX 9502 (95 wt% TATB) both for planar and oblique input shocks. In this work, we build on previous results by performing cylinder expansion (CYLEX) tests where the explosive charge is comprised of a faster core of PBX 9501 (95 wt% HMX) inside a slower annulus of PBX 9502. The detonation in the faster PBX 9501 drives an oblique shock into the adjacent PBX 9502, and an annular transverse initiating layer (IL) results. In the test geometry, the IL travels steadily down the length of the test after a short run distance. At radial positions beyond the IL, an annular region of detonating PBX 9502 is observed. Using standard CYLEX test diagnostics, we infer the total energy release of this experiment. By making the assumptions that (1) the combined energy release is comprised of contributions from detonating PBX 9501, detonating PBX 9502, and the IL in the PBX 9502 and (2) mass-specific energy release for the detonating explosives is approximately the same as typically observed for each explosive, the IL energy release and reaction efficiency can be computed. Results are compared to prior results for a similar geometry, and indicate that while shock deadened PBX 9502 does not detonate promptly, it does eventually release a significant portion of its chemical potential energy over longer timescales on the order of 10 µs.