计及动态冲击挤进过程的埋头式弹药内弹道特性

为能够精确预测埋头式弹药的内弹道特性，了解埋头式弹丸动态冲击挤进过程中尼龙弹带的变形形态、失效模式及刻槽形成机理。利用LS-DYNA软件，建立计及挤进系统复杂结构和埋头式弹丸动态冲击特性的三维有限元模型，并进行模拟仿真。结合埋头式弹药两级点火和火药程序燃烧的新原理，进一步建立埋头式弹丸挤进过程初始内弹道与挤进完成后内弹道的一体化模型，并对比数值计算与试验测试结果。对比结果表明：弹带材料直接受膛线作用发生断裂失效模式主要以剪切失效为主，挤进过程分为初期依靠初始速度减速挤进与后期火药燃气推动加速挤进阶段，两阶段弹带材料受膛线挤压均产生大变形，相应的挤进阻力也较大，最终通过拟合得到了弹丸动态冲击挤进阻力表达式，并与内弹道方程耦合建立了埋头式弹丸内弹道一体化精确模型，该模型计算结果与试验吻合较好，验证了其准确性，为今后这种新型弹药的装药结构设计提供了有益的参考。

Study on Interior Ballistic Characteristics of Cased Telescoped Ammunition with Dynamic Impact Engraving Considered

To accurately predict the interior ballistic characteristics of telescoped ammunitions，the deformation，failure mode，and groove formation mechanism of the nylon cartridge belt during the dynamic impact engraving process of the telescoped ammunition are studied. A three-dimensional finite element model considering the complex structure of the engraving system and the dynamic impact characteristics of the telescoped projectile is established by using LS-DYNA software，and simulation is performed.On this basis，considering the new principle of two-stage ignition and programmed combustion of the ammunition，an integrated model for the initial interior ballistics of the ammunition during and after engraving is also established. The numerical results are compared with the experimental results.The results show that the fracture failure mode of the belt material under the action of rifling is mainly shear failure，and the engraving process can be divided into two stages. The belt material is deformed significantly due to the extrusion of rifling during both stages，so the corresponding extrusion resistance is also evident. Eventually，the dynamic impact extrusion resistance of the projectile is expressed by fitting. The results of the model are in good agreement with the test results，verifying the accuracy of the model and providing a useful reference for the design of the charge structures of such novel ammunition.