A melt-cast Duan-Zhang-Kim mesoscopic reaction rate model and experiment for shock initiation of melt-cast explosives

A melt-cast Duan-Zhang-Kim (DZK) mesoscopic reaction rate model is developed for the shock initiation of melt-cast explosives based on the pore collapse hot-spot ignition mechanism. A series of shock initiation experiments was performed for the Comp B melt-cast explosive to estimate effects of the loading pressure and the particle size of granular explosive component, and the mesoscopic model is validated against the experimental data. Further numerical simulations indicate that the initial density and formula proportion greatly affect the hot-spot ignition of melt-cast explosives.     

Effect of the end cap on the fragment velocity distribution of a cylindrical cased charge

The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been con-ducted to predict the fragment velocity distributions along the axis of cylindrical cased charges with end caps. This paper presents a study of the velocity distribution of fragments caused by the explosion of a cylindrical cased charge with end caps. The fragment velocity distribution and the end cap velocity were determined by an X-ray radiography method, and the axial fragment distribution was determined by witness plates. It was found that the velocities of fragments, especially near the edge, were increased when the end caps were added, and the position of maximum velocity is closer to the non-detonation end. The fragment velocities were increased, and the fragment projection range was decreased with the increase of the thickness of the end cap. A formula for fragment velocity distributions of a cylindrical cased charge with end caps, which is based on Huang's formula, was proposed by the theoretical analysis and data fitting and validated experimentally. The results indicate that the proposed formula is accurate in predicting the fragment velocity distribution along the axis of a cylindrical cased charge with end caps detonated at one end.     

Numerical study on the case effect of a bomb air explosion

When considering the bomb explosion damage effect, the air shock wave and high-speed fragments of the bomb case are two major threats. In experiments, the air shock wave was studied by the bare ex-plosives superseding the real cased bomb; in contrast, the bomb case influence was ignored to reduce risk. The air explosion simulations of the MK84 warhead with and without the case were conducted. The numerical simulation results showed that the bomb case significantly influenced the shock wave generated by the bomb: the spatial distribution of shock wave in the near field changed, and the peak value of shock wave was reduced. Breakage of the case and kinetic energy of the fragmentation consumed 3 and 38% of the explosion energy, respectively. The increasing factors of the peak over-pressure induced by the bare explosive on the ground and in the air were 1.43-3.04 and 1.37-1.57, respectively. Four typical stages of case breakage were defined. The mass distribution of the fragments follows the Mott distribution. The initial velocity distribution of the fragments agreed well with the Gurney equation.     

Explosion temperature mapping of emulsion explosives containing TiH2 powders with the two-color pyrometer technique

In the study, the two-color pyrometer technique was used to measure the transient temperature field of emulsion explosives with different contents of TiH₂ powders. The experimental results showed that the introduction of TiH₂ powders could significantly increase the explosion temperature and fireball duration of emulsion explosive. When emulsion explosives were ignited, the average explosion temperature of pure emulsion explosive continuously decreased while emulsion explosives added with TiH₂ powders increased at first and then decreased. When the content of TiH₂ powders was 6 mass%, the explosion average temperature reached its maximum value of 3095 K, increasing by 43.7% as compared with that of pure emulsion explosive. In addition, the results of air blast experiment and explosion heat test showed that the variation trends of shock wave parameters, explosion heat and theoretical explosion temperature of emulsion explosives with different contents of TiH₂ powders were basically consistent with that of explosion temperature measured by the two-color pyrometer technique. In conclusion, the two-color pyrometer technique would be conducive to the formula design of emulsion explosive by understanding the explosion temperature characteristics.     

预制缺陷柱壳结构的等效裂纹分析方法

针对传统有限元法在分析预制缺陷柱壳时出现的应力/应变计算精度不足、无法有效指导工程实践的问题,提出了一种具有高冗余度的等效裂纹分析方法。将预制缺陷视作典型裂纹,基于奇异裂纹元法对其进行裂纹稳定性分析,并根据稳定性分析结果来评估预制缺陷柱壳的结构完整性。通过该方法得到的分析结果具有比常规有限元分析更高的可靠性,对于导弹线式爆炸分离装置等工作环境恶劣、风险系数较高的预制缺陷柱壳结构而言,该方法有助于提升其设计的安全裕度,具有一定的工程实用性。     

烟花爆竹及民用爆炸物品建筑工程消防审核验收探讨

结合烟花爆竹、民用爆炸物品的生产、储存火灾危险性,探讨了公安机关消防机构如何对烟花爆竹、民用爆炸物品生产、储存场所进行消防设计审核验收,以起到加强烟花爆竹、民用爆炸物品生产、储存建筑消防安全的目的。     

纵火战斗部爆炸分散仿真研究

在试验的基础上,从炸药对纵火炬的驱动和纵火炬在空中飞散两个方面,对其在战斗部静爆和动态飞行时的爆炸分散进行了仿真研究,研究结果对纵火弹的具体设计具有重要的参考价值。     

爆电换能的理论分析

考虑了铁电介质的介电松弛和电导率松弛,计及冲击波阵面在样品中传播过程的影响,改进了垂直模式冲击波加载铁电陶瓷电响应的理论,且理论分析与实验结果基本一致。     

圆柱形容器爆炸焊接数值模拟与实验

针对深空探测采样容器的特殊要求,进行爆炸焊接严实密封技术研究。利用非线性动力学软件进行铝质柱形容器爆炸焊接数值模拟,得到各种焊接初始参数的影响规律,确定较佳焊接初始参数及容器结构尺寸,并进行实验验证。实验结果表明:外盖角度为7°时,1mm壁厚外盖配4mm壁厚内圆柱或2mm壁厚外盖配6mm壁厚内圆柱,配以较合适炸药厚度,密实焊接效果较理想。研究结果为深空探测采样容器结构设计提供了较好的参考。     

煤层气加气站火灾爆炸危险性分析及消防对策

根据太原市煤层气加气站的具体情况,从设备安全、规范化安全管理等方面分析了CNG加气站的火灾爆炸危险性,探讨煤层气加气站消防安全的技术措施及对策。