基于离散单元法的发射装药挤压破碎模拟实验

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。

Simulational experiment on compression and fracture of propellant charge based on the discrete element method

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.