Simulational experiment on compression and fracture of propellant charge based on the discrete element method
-
摘要: 为了揭示发射装药破碎引起的膛炸现象,急需进行相应装药结构下发射装药挤压破碎数值模拟研究。以硝胺花边十九孔发射药为研究对象,基于离散单元法建立了发射装药挤压破碎模拟系统,同时进行了发射装药动态挤压破碎实验,通过数值模拟与实验获得了不同冲击载荷下的破碎发射装药和挤压应力;分别对获得的破碎发射装药进行了密闭爆发器数值模拟和实验。结果表明:模拟与实验获得的发射装药挤压应力时间历程、密闭爆发器压力时间曲线和起始动态活度比的一致性较好,实验验证了发射装药挤压破碎模拟系统的有效性及合理性。该模拟系统具有重大工程应用价值,为高能发射装药冲击破碎过程和发射装药发射安全性研究奠定了基础。Abstract: In order to reveal the mechanisms of gun breech-blow phenomenon caused by the fracture of propellant charge, it is urgent to carry out the simulation research on the compression and fracture of propellant charge under the corresponding charge structure. Through the analysis of the mechanical environment in the gun bore and the fracture progress of propellant charge, the discrete element method was employed to simulate the compression and fracture of propellant charge. The lace 19-hole propellant for the large caliber artillery was taken as the research object, a simulation system of compression and fracture of propellant charge was constructed using the EDEM software. And the Hertz-Mindlin contact model parameters were determined by using the drop hammer impact test of the single propellant at low temperature (–40 ℃). Then the compression andfracture simulation of the propellant charge was verified through the dynamic compression and fracture test of the propellant charge at low temperature (–40 ℃). Under the same impact load, the fracture of propellant charges and the compression stress-time curves of propellant charge were achieved by test and simulation, respectively. Using the obtained fracture propellant charge, the closed bomb simulation and test were carried out respectively. Among them, a combustion function based on the discrete element method was used to represent the gas generation law of the simulation fracture propellant charge. Finally, the initial dynamic vivacity ratio of the fracture propellant charge was processed according to the pressure-time curve. The researchresults show that the time histories of compression stress of propellant charge, the closed bomb pressure-time curves, and the initial dynamic vivacity ratios obtained by simulation and test are in good agreement with each other, indicating the designed simulation system is effective and reasonable. The research method has great engineering application value, which lays a foundation for the study of the impact fracture process of high-energy propellant charge and the launch safety of propellant charge.
-
表 1 数值模拟参数与结果
Table 1. Model parameters and simulation results
序号 法向黏结刚度/(GN·m−3) 切向黏结刚度/(GN·m−3) 法向临界应力/MPa 切向临界应力/MPa 最大应力/MPa 1 449.55 134.87 120 36.0 87.31 2 449.55 134.87 125 37.5 90.95 3 449.55 134.87 130 39.0 95.31 4 449.55 134.87 135 40.5 98.24 5 449.55 134.87 140 42.0 102.67 6 449.55 134.87 150 45.0 110.14 表 2 实验条件和结果
Table 2. Experiment conditions and results
序号 燃烧室最大压力/MPa 挤压应力峰值/MPa 1 37.46 3.96 2 40.43 11.06 3 44.81 15.35 表 3 数值模拟结果
Table 3. Simulation results
序号 挤压应力峰值/MPa 黏结键连接个数 1 3.92 18 498 2 9.14 15 190 3 13.34 12 233 表 4 数值模拟与实验起始动态活度比对比
Table 4. Comparision of initial dynamic vivacity ratios in simulation and experiment
序号 数值模拟的起始动态活度比 实验的起始动态活度比 误差/% 1 1.144 1.189 3.78 2 1.570 1.628 3.56 3 1.942 2.067 6.05 -
[1] 芮筱亭, 贠来峰, 王国平, 等. 弹药发射安全性导论[M]. 北京: 国防工业出版社, 2009: 1–5.RUI X T, YUN L F, WANG G P, et al. Direction to lanch safety of ammunition [M]. Beijing: National Defense Industry Press, 2009: 1–5. [2] 芮筱亭, 冯宾宾, 王燕, 等. 发射装药发射安全性评定方法研究 [J]. 兵工学报, 2015, 36(1): 1–11. DOI: 10.3969/j.issn.1000-1093.2015.01.001.RUI X T, FENG B B, WANG Y, et al. Research on evaluation method for launch safety of propellant charge [J]. Acta Armamentarii, 2015, 36(1): 1–11. DOI: 10.3969/j.issn.1000-1093.2015.01.001. [3] GAZONAS G A, FORD J C. Uniaxial compression testing of M30 and JA2 gun propellant using a statistical design strategy [J]. Experimental Mechanics, 1992, 32(2): 154–162. DOI: 10.1007/BF02324727. [4] 陈言坤, 甄建伟, 武慧恩, 等. 粒状发射药动态破碎研究进展 [J]. 爆破器材, 2014, 43(1): 43–48. DOI: 10.3969/j.issn.1001-8352.2014.01.010.CHEN Y K, ZHEN J W, WU H E, et al. Research progress of dynamic fracture of granular propellant [J]. Explosive Materials, 2014, 43(1): 43–48. DOI: 10.3969/j.issn.1001-8352.2014.01.010. [5] CUNDALL P A. A computer model for simulating progressive, large-scale movements in block rock systems [C] // Symposium of International Society of Rock Mechanics. Nancy, France, 1971. [6] JIANG S P, RUI X T, HONG J, et al. Numerical simulation of impact breakage of gun propellant charge [J]. Granular Matter, 2011, 13(5): 611–622. DOI: 10.1007/s10035-011-0276-1. [7] 王燕, 芮筱亭, 宋振东, 等. 初始堆积对发射装药底部挤压应力的影响 [J]. 爆炸与冲击, 2014, 34(5): 560–566. DOI: 10.11883/1001-1455(2014)05-0560-07.WANG Y, RUI X T, SONG Z D, et al. Effect of original packing on compression stress at the bottom of propellant bed [J]. Explosion and Shock Waves, 2014, 34(5): 560–566. DOI: 10.11883/1001-1455(2014)05-0560-07. [8] EDEM tutorial [M]. Edinburgh: DEM Solutions, 2011. [9] POTYONDY D O, CUNDALL P A. A bonded-particle model for rock [J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(8): 1329–1364. DOI: 10.1016/j.ijrmms.2004.09.011. [10] QUIST J. Cone crusher modelling and simulation [D]. Göteborg: Chalmers University of Technology, 2012: 1–45. [11] 夏露. 高能材料结构和性能的分子动力学模拟[D]. 苏州: 苏州大学, 2008: 46.XIA L. Molecular dynamics simulations of the structures and properties of highly energetic materials [D]. Suzhou: Suzhou University, 2008: 46. [12] 徐浩, 芮筱亭, 郁兆华, 等. 发射装药挤压应力与破碎规律研究 [J]. 火炸药学报, 2012, 35(4): 61–68. DOI: 10.3969/j.issn.1007-7812.2012.04.016.XU H, RUI X T, YU Z H, et al. Study on extrusion stress and fracture law of propellant charge [J]. Chinese Journal of Explosives and Propellants, 2012, 35(4): 61–68. DOI: 10.3969/j.issn.1007-7812.2012.04.016. [13] ZHANG R H, RUI X T, WANG Y, et al. Study on the change of gas generation law caused by fracture of propellant charge [J]. Journal of Energetic Materials, 2018, 36(4): 454–467. DOI: 10.1080/07370652.2018.1486895.