炸药撞击感度试验的研究

综述了炸药撞击感度的背景知识，试验现象的判定以及撞击感度与分子结构的关系。指出了撞击感度的研究方向。     

Model of Impact Initiation of Composite Explosive Solid Systems

A model of mechanical initiation of solid explosives, applicable for analysis of sensitivity of individual substances and composite explosives, is developed. The model includes a system of equations of work softening of a high explosive charge under an impact, resulting dissipative heating, and heat release due to chemical reactions between the components of the explosive mixture. The critical parameters and reaction kinetics were numerically calculated for initiation of charges consisting of a mixture of ammonium perchlorate and polymethylmethacrylate. The results are compared to experimental data on sensitivity of this mixture to the impact. Key words: high explosive, impact, explosion, impact sensitivity.     

搅拌轴临界转速近似计算方法的比较

阐述了搅拌轴临界转速的几种近似方法的特点,并与国内现行标准HG/T20569-94作了比较,并得出了相关结论。     

Explosive Mixtures for Explosive Welding of Thin Foils: Part 2. RDX–Baking Soda Mixtures

Explosive mixtures of RDX powder and baking soda have been investigated. It was found that the size of the RDX particles had crucial influence on the detonation properties of such explosives. The suggested mix of explosives can be recommended for use in explosive welding and some other applications.     

陶瓷粉末中固相物质导热系数的计算方法

对于未知具体组成成分的微粒介质,例如瓷土、沙子、陶瓷粉末等,包含的固相物质的真实导热系数很难得出。本文提供一种计算微粒介质中固相物质导热系数的方法,只需简单测量微粒介质在绝对干燥和绝对润湿的状态下的导热系数,即可计算出微粒介质中固相物质的导热系数,并对Al2O3陶瓷粉末进行实验测量,将实验计算的结果和理论数据进行比较,结果表明,公式计算值与理论值有较好的一致性。     

含铝炸药水中爆炸能量输出结构

通过测定、计算、分析不同类型炸药水中爆炸能量输出参数，揭示了不同类型炸药在水中爆炸能量输出特性，分析了高威力含铝炸药组成铝氧比对水中爆炸能量输出结构的影响。研究结果表明，在一定的对比距离上，当铝氧比为0．35—0．40时，水中爆炸冲击波能达到最高；当铝氧比增大到1．00时，其水中爆炸的气泡能接近最大值。这种方法可使水中爆炸装置能量输出结构与爆炸目标的易损性相匹配，借以提高温炸毁伤效果。     

EAK基熔铸分子间炸药的能量和撞击感度

通过水下爆炸试验研究了RDX和HMX对EAK基熔铸分子间炸药水下能量的影响。结果表明,RDX和HMX对EAK基混合炸药起到明显的增能作用,但对含铝和非含铝体系有不同的作用效果。爆速和撞击感度测定表明,EAK—RDX混合炸药爆轰的理想化程度和稳定性及撞击感度随RDX含量的增加而增加。从能量和撞击感度两个方面综合考虑,RDX的较佳加入量应为20％～30％。     

Simulation of Explosive Welding with ANFO Mixtures

The work described here arose from a study into explosive welding. As part of that study, the impact velocity of stainless steel and titanium plates to grazing detonation of ANFO/perlite, the velocity of detonation were measured. Computer simulation required a new model which copes with an equation of state of low explosives.     

Explosive Strength and Impact Sensitivity of Several PBXs Based on Attractive Cyclic Nitramines

Plastic explosives based on different cyclic nitramines with different polymeric matrices were prepared and studied. The used polymeric matrices were fabricated on the basis of polyisobutylene (PIB), acrylonitrile‐butadiene rubber (ABR), Viton A, and polydimethyl‐siloxane as binders, whereas the nitramines named RDX (1,3,5‐trinitroperhydro‐1,3,5‐triazine), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine), BCHMX (cis‐1,3,4,6‐tetranitrooctahydroimidazo‐[4,5‐d]imidazole) and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) were used as explosive fillers. Commercial Semtex 10, based on pentaerythritol tetranitrate (PETN), was used for comparison. Impact sensitivity, loading density, ρ, detonation velocity, D, and relative explosive strength (RS) measured by ballistic mortar were determined. It was concluded that plastic BCHMX based on Viton A or PIB‐matrix exhibits higher RS compared with PBXs based on RDX and HMX. Correlations between RS and the impact sensitivity, the ρD² term and the square of the detonation velocity were studied and discussed. The results confirm the well‐known fact that increasing the performance is usually accompanied by an increase in the sensitivity of the explosives. In this connection, Viton A enables achieving a high RS, but with a relatively high sensitivity of the PBXs, whereas the polydimethyl‐siloxane matrix should perhaps give PBXs with optimum explosive strength and sensitivity parameters.     

Approximate Analytical Method for Calculating the Time Characteristics of Ignition of a Gas Mixture by a Heated Body

Analytical expressions for calculating the time characteristics of ignition of gas mixtures by a heated body are obtained for the first time with the help of the wave theory of ignition. It is shown that ignition can occur in three different modes: kinetic (onetemperature), diffuse (twotemperature), and transitional, which combines the properties of both diffusion and kinetic modes. The parametric region of implementation of each possible ignition mode is determined. It is found that the transition from the kinetic to the diffusion mode occurs as the temperature of the heater changes only by one characteristic interval and is accompanied by a jumplike decrease both in the ignition delay and in the amount of energy necessary for combustion initiation. A relation is established between the laws of ignition and diffusion combustion of a single particle and parameters of ignition of the gas mixture of a given sort of particles. It is shown that there is a minimum in the dependences of the time of establishing of the zero gradient of ₀ on Semenov's criterion. The value of ₀ is found to be minimum if the heater temperature is higher than the temperature of ignition of a single particle by one characteristic interval. The numerical solution of the initial system of equation confirms the validity of the basic assumptions and results of the approximate analysis. The error in determining the time characteristics of ignition with the help of approximate formulas is lower than 50%. For the kinetic mode of ignition, a transformation of the time and space scales is found, such that the time characteristics of ignition in new dimensionless variables become independent of the mass concentration of particles.     

Approximate Method of Calculating Critical Shock Initiation conditions and run distance to detonation

An approximate model for pressure buildup behind the front of an initiating shock wave is developed. This model leads to the widely used P²t initiation criterion, but the pressure index is not limited to a value of two. Expressions for wave run time and distance to detonation are also obtained. The use of the model is illustrated using explosives widely discussed in the literature. It is shown that critical shock initiation and run distance to detonation can be rapidly estimated to good approximation over a wide range of shock conditions from the results of one or two relatively simple experiments. The calculational method may be useful for various applications.     

Relative Explosive Strength of Some Explosive Mixtures Containing Urea and/or Peroxides

Several mixtures, based on urea derivatives and some inorganic oxidants, including also alumina, were studied by means of ballistic mortar techniques with TNT as the reference standard. The detonation pressure(P), detonation velocity(D), detonation energy(Q), and volume of gaseous product at standard temperature and pressure (STP), V, were calculated using EXPLO5 V6.3 thermochemical code. The performance of the mixtures studied was discussed in relation to their thermal reactivity, determined by means of differential thermal analysis (DTA). It is shown that the presence of hydrogen peroxide in the form of its complex with urea (i.e. as UHP) has a positive influence on the explosive strength of the corresponding mixtures which is linked to the hydroxy-radical formation in the mixtures during their initiation reaction. These radicals might initiate (at least partially) powdered aluminum into oxidation in the CJ plane of the detonation wave. Mixtures containing UHP and magnesium are dangerous because of potential auto-ignition.     

Sensitivity and Evaluation of Explosive Substances

Explosion sensitivity involves many complex factors. A theory for evaluating and a method for testing have to be established. We have proposed an explosion sensitivity theory for explosive substances and have also tested the evaluating method. The results of our research reveal a satisfactory mutual relation between both theoretical and experimental values.     

乳化炸药撞击感度的测试方法

建立了一种适应乳化炸药特性的撞击感度测试方法。该方法采用现有的WL-1型落锤仪,在击柱间加石英砂测其特性落高,通过对比不同乳化炸药特性落高值的大小来对比不同乳化炸药的撞击感度。该方法科学可靠．简便易行,可以分辩不同乳化炸药之间的撞击感度差异。试验表明,不同品种不同工厂生产的乳化炸药,其撞击感度可能有较大的差异。     

用近似Broekhoff方程计算孔径分布

本文对计算孔径分布的Broekhoff方程做了简化,得到一组近似方程,实例计算结果证明它和原方程等效.近似方程的优点在于能制成专用机与吸附仪联用,加快数据处理.近似方程的适用范围为:10(?)—300(?)     

DADE及其混合炸药的机械感度

为了解DADE以及含DADE的混合炸药的安全性能,用显微镜研究了DADE混合炸药降感机理。结果表明,在相同的试验条件下,DADE与TATB、NTO的机械感度相当,具有优良的安全性能;DADE粒度的大小对其感度影响很大,感度随粒度的减小而升高;在B炸药配方中,用DADE部分代替RDX后感度没有明显改变,完全代替RDX后降感效果十分明显。研究表明,DADE颗粒的合理级配以及表面包覆是降低DADE机械感度的重要途径。     

火炸药药柱撞击感度试验装置及方法

为了提高火炸药药柱撞击感度测试的试验手段,建立了一套新的炸药药柱撞击感度测试系统,并对系统的主要技术指标进行了验证。设计了试验方法,对不同成型炸药药柱和不同尺寸的推进剂进行了撞击试验。结果表明,试验结果气体检测判定法明显好于传统的方法,药粉与药柱由于结构的不同,试验结果也不完全一致,即使相同种类的药由于尺寸不同也可能带来结果的差异。     

Large-Scale Fragment Impact Sensitivity Test Results of a Melt Castable,General Purpose,Insensitive High Explosive

The thermoplastic explosive (TE-T7005) was developed as a General Purpose (GP) Insensitive High Explosive (IHE) candidate due to a number of factors including: low small scale sensitivity characteristics; low processing cost; theoretical high performance; re-meltability (with associated economic and environmental benefits); and potential endothermic characteristics during cook-off. Theoretical high performance and excellent cook-off characteristics were verified with subsequent large scale tests^(1-4). This paper will report on large-scale fragment impact sensitivity test results for the composition TE-T7005. Fragment cubes measuring 1.27 cm×1.27 cm×1.27 cm were fired at and impacted two separate test units (loaded with the explosive TE-T7005) at an average velocity of 8670 ft/s (2643.6 m/s). Each reaction was judged to be a brief burning that was not sustained. No blast pressures from the reaction of the test units were detected, indicating that no significant reaction occurred. The reaction response was somewhat milder compared with HTPB analogs of TE-T7005⁽⁵⁾.     

纳米Al对RDX基炸药机械感度和火焰感度的影响

采用机械混合法制备了含纳米Al的RDX基混合炸药,测试了其机械感度和火焰感度,用扫描电镜表征了纳米Al及其炸药的表面形貌,分析了感度变化的原因。结果表明,加入纳米Al后,RDX基炸药的撞击感度、摩擦感度和火焰感度增大;随着纳米Al含量的增加,撞击感度、摩擦感度和火焰感度明显增大;且含纳米Al炸药的撞击感度、摩擦感度和火焰感度均高于含微米Al炸药。纳米Al及含纳米Al炸药均存在微量团聚现象,在一定程度上影响了含纳米Al的RDX基炸药的感度。     

A Simple Theoretical Method for Determining the Sensitivity of Bare Explosives to Detonation by Projectile Impact

The Walker‐Wasley Critical Initiation Energy, E _c, cited by several authors as a means of comparing the sensitivity of explosives to projectile impact, is imprecise. Moreover, energy is not a necessary and sufficient condition upon which to compare sensitivities, since it might be delivered over picoseconds or years with vastly different results. Shock to detonation initiation conditions are conventionally represented by log −log relationships in Pop Plots. Historical experimental flat‐fronted projectile attack data for two explosives, PBX 9404 and Tetryl were transformed using Hugoniot data into log −log form like Pop Plots. Consistent with recent research at LASL and LLNL in the US, near coincidence between such plots and Pop Plots was demonstrated. This procedure led to a method of comparing the sensitivities of these and four other explosives, two types of Composition B, TNT and Nitroguanidine/Estane (95/5), to shock initiation by projectile impact. A slight modification of this procedure can be used to generate critical projectile velocity vs. diameter curves from Hugoniot and Pop Plot data which confirm the experimental data for PBX 9404 and Tetryl. An alternative comparative sensitivity criterion to that of Walker and Wasley that is derived from Pop Plot data is proposed based on the critical power per unit mass of explosive transmitted from the initiating shock.