弹体高速侵彻混凝土靶质量损失和头形钝化的数值模拟研究

NUMERICAL STUDY ON MASS LOSS AND NOSE-BLUNTING FOR THE PROJECTILE DURING THE HIGH-SPEED PENETRATION ON CONCRETE TARGET

弹体高速侵彻混凝土靶体时,弹靶间相互作用引起的弹体质量损失和头形钝化效应能够导致弹体结构和弹道严重失稳,从而降低弹体侵彻效能.假设侵彻过程中靶体对弹体的摩擦功全部转化为引起弹体表面材料熔融和剥离的热能,弹靶间摩擦为一般形式的摩尔库伦摩擦,论文建立了考虑质量损失和头形钝化的半刚性弹二维弹道的计算方法并编制了相关程序,该程序避免了采用速度相关摩擦系数得到摩擦功解析解的困难,并可计算侵彻过程中所有参数(侵彻深度、质量损失、速度、加速度等),且可直接推广应用于斜侵彻问题.在此基础上,讨论了指数衰减和零滑动摩擦系数形式,通过对比弹体质量损失和侵彻后头形钝化计算结果与实验数据,验证了论文方法从适用范围、物理意义和理论基础方面的适用性和优越性.数值计算结果表明,将滑动摩擦系数取为零忽略了弹靶间摩擦力与侵彻瞬时速度的关系,故其进一步推广应用有待商榷.

During the high-speed penetration on concrete target,the mass abrasion and nose-blunting of the projectile induced by the projectile-target mutual interactions may lead to the structural and ballistic trajectory instability of the projectile,thus the penetration efficiency of the penetrator is reduced obviously.Assuming that the frictional energy between the projectile and the target is totally transferred into the melt heat energy of the projectile and the friction between the target and the projectile is Mohr-coulomb form,the computational method of the variation of the projectile nose is established,and the 2-D finite difference program considering the mass loss and nose-blunting of the projectile is complicated.This program avoids the difficulties to acquire the friction work when using the velocity-depend sliding friction and can calculate all parameters during the penetration(the depth of penetration,mass lose,velocity,acceleration,etc.)and can be easily expand into oblique penetration directly.Additionally,zero and exponential damping coefficient of sliding friction were discussed,and the proposed method and program were verified by comparing the predicted mass loss and nose-blunting with the tests data.Simulation results indicated that zero coefficient of sliding friction assumption remains open to question since it neglects that the friction between the target and the projectile depend on the penetration velocity.