某埋头式弹丸动态冲击挤进特性的研究

为研究埋头式弹丸动态冲击挤进过程中弹带在坡膛处产生的高应变率塑性变形及断裂失效问题，考虑到埋头式弹药二次点火和火药程序燃烧的特殊性，将试验测得的弹底压力及弹丸一次上膛速度作为数值仿真模型的初始边界条件，建立了基于身管及埋头式弹丸结构特性、材料大变形和损伤效应等因素的三维有限元模型. 基于LS-DYNA软件，采用显式数值计算方法，对埋头式榴弹动态冲击挤进过程进行了研究，获得了弹丸冲击挤进阻力的变化规律，并分析了弹带表面刻槽的成形过程及应力应变特征. 结果表明:当埋头式榴弹的紫铜弹带冲击挤入坡膛时，经历了从弹性变形到塑性变形，并最终断裂失效的过程. 当弹带完全挤入身管全深膛线，整个动态冲击挤进过程结束，弹带表面形成了较深的刻槽，并与身管膛线紧密贴合，其间冲击挤进阻力呈现出强烈的非线性变化. 

Study on Dynamic Impact Engraving Characteristic of Cased Telescoped Ammunition

To study the high-strain-rate plastic deformation and fracture failure of the projectile belt at the slope during the dynamic impact extrusion process of cased telescoped ammunition, considering the particularity of the secondary ignition of the cased telescoped ammunition and the combustion of the gunpowder program, with the bottom pressure of the projectile and the one-load speed of the projectile obtained from the test taken as the initial boundary conditions of the numerical simulation model, a three-dimensional finite element model was built based on the structural characteristics of the body tube and the cased telescoped ammunition, large deformation and damage effect of the material. Based on the LS-DYNA software, the dynamic engraving process of the cased telescoped ammunition was studied using an explicit numerical calculation method. The variation law of projectile impact extrusion resistance was obtained, and the forming process and stress strain characteristics of the grooves on the surface of the elastic belt were analyzed. The results show that when the copper belt of the cased telescoped ammunition is violently engraved into the slope chamber, it undergoes a process from elastic deformation to plastic deformation and finally to fracture failure. When the elastic belt is completely engraved into the body tube full depth rifling, the entire dynamic impact engraving process is over, and a deep groove is formed on the surface of the elastic belt, which closely adheres to the body tube rifling, during which the impact engraving resistance shows a strong nonlinear change.