Launch safety of explosive charges has become an urgent problem to be solved by all countries in the world aslaunch situation of ammunition becomes consistentlyworse.However, the existing numericalmodels have differen...Launch safety of explosive charges has become an urgent problem to be solved by all countries in the world aslaunch situation of ammunition becomes consistentlyworse.However, the existing numericalmodels have differentdefects. This paper formulates an efficient computational model of the combustion of an explosive charge affectedby a bottom gap in the launch environment in the context of the material point method. The current temperatureis computed accurately from the heat balance equation, and different physical states of the explosive charges areconsidered through various equations of state. Microcracks in the explosive charges are described with respectto the viscoelastic statistical crackmechanics (Visco–SCRAM) model. Themethod for calculating the temperatureat the bottomof the explosive charge with respect to the bottomgap is described. Based on this combustionmodel,the temperature history of a Composition B (COMB) explosive charge in the presence of a bottom gap is obtainedduring the launch process of a 155-mm artillery. The simulation results show that the bottom gap thickness shouldbe no greater than 0.039 cm to ensure the safety of the COM B explosive charge in the launch environment. Thisconclusion is consistent with previous results and verifies the correctness of the proposed model. Ultimately, thispaper derives amathematical expression for themaximumtemperature of the COMB explosive chargewith respectto the bottomgap thickness (over the range of 0.00–0.039 cm), and establishes a quantitative evaluationmethod forthe launch safety of explosive charges.The research results provide some guidance for the assessment and detectionof explosive charge safety in complex launch environments.展开更多
对采自东太平洋 CC 区西部的 WPC1101重力活塞柱样进行了岩石磁学、古地磁极性地层及古生物地层年代学研究工作。等温剩余磁化强度（IRM）、磁滞回线和反向场退磁曲线测试结果表明，沉积物中的磁性矿物主要为磁铁矿，仅在柱状样底部存...对采自东太平洋 CC 区西部的 WPC1101重力活塞柱样进行了岩石磁学、古地磁极性地层及古生物地层年代学研究工作。等温剩余磁化强度（IRM）、磁滞回线和反向场退磁曲线测试结果表明，沉积物中的磁性矿物主要为磁铁矿，仅在柱状样底部存在少量赤铁矿/针铁矿。340~350 cm 发育的埋藏结核层，标志着一处沉积间断的存在；60~336 cm 发育上新世晚期的硅藻化石 Cosinodiscus nodulifer ，但古地磁极性地层缺失上新世第四纪的2r 反极性时；0~60 cm 见第四纪标准化石 Pseudoenuotia doliolus 、Spongaster tetras ，且顶部缺失1正极性时。综合对比古生物地层学、磁性地层学以及邻近区域地层学特征，认为该柱状样记录了从晚渐新世至第四纪的沉积历史，期间存在晚渐新世至早上新世、上新世晚期至第四纪早期及第四纪晚期3个时期的沉积间断，上述沉积间断的形成可能是南极底流的形成与增强、CCD 界面抬升及海底侵蚀作用增强共同控制的结果。展开更多
基金the Natural Science Foundation of Heilongjiang Province,China(LH2019A008).
文摘Launch safety of explosive charges has become an urgent problem to be solved by all countries in the world aslaunch situation of ammunition becomes consistentlyworse.However, the existing numericalmodels have differentdefects. This paper formulates an efficient computational model of the combustion of an explosive charge affectedby a bottom gap in the launch environment in the context of the material point method. The current temperatureis computed accurately from the heat balance equation, and different physical states of the explosive charges areconsidered through various equations of state. Microcracks in the explosive charges are described with respectto the viscoelastic statistical crackmechanics (Visco–SCRAM) model. Themethod for calculating the temperatureat the bottomof the explosive charge with respect to the bottomgap is described. Based on this combustionmodel,the temperature history of a Composition B (COMB) explosive charge in the presence of a bottom gap is obtainedduring the launch process of a 155-mm artillery. The simulation results show that the bottom gap thickness shouldbe no greater than 0.039 cm to ensure the safety of the COM B explosive charge in the launch environment. Thisconclusion is consistent with previous results and verifies the correctness of the proposed model. Ultimately, thispaper derives amathematical expression for themaximumtemperature of the COMB explosive chargewith respectto the bottomgap thickness (over the range of 0.00–0.039 cm), and establishes a quantitative evaluationmethod forthe launch safety of explosive charges.The research results provide some guidance for the assessment and detectionof explosive charge safety in complex launch environments.
文摘对采自东太平洋 CC 区西部的 WPC1101重力活塞柱样进行了岩石磁学、古地磁极性地层及古生物地层年代学研究工作。等温剩余磁化强度（IRM）、磁滞回线和反向场退磁曲线测试结果表明，沉积物中的磁性矿物主要为磁铁矿，仅在柱状样底部存在少量赤铁矿/针铁矿。340~350 cm 发育的埋藏结核层，标志着一处沉积间断的存在；60~336 cm 发育上新世晚期的硅藻化石 Cosinodiscus nodulifer ，但古地磁极性地层缺失上新世第四纪的2r 反极性时；0~60 cm 见第四纪标准化石 Pseudoenuotia doliolus 、Spongaster tetras ，且顶部缺失1正极性时。综合对比古生物地层学、磁性地层学以及邻近区域地层学特征，认为该柱状样记录了从晚渐新世至第四纪的沉积历史，期间存在晚渐新世至早上新世、上新世晚期至第四纪早期及第四纪晚期3个时期的沉积间断，上述沉积间断的形成可能是南极底流的形成与增强、CCD 界面抬升及海底侵蚀作用增强共同控制的结果。
