基于拟流体模型的SPH新方法及其在弹丸超高速碰撞薄板中的应用

摘要

引入颗粒动力学理论(拟流体模型)建立了适用于超高速碰撞的SPH新方法.将超高速碰撞中处于损伤状态的碎片等效为拟流体,在描述其运动过程中引入了碎片间相互作用和气体相对碎片的作用.采用该方法对球形弹丸超高速碰撞薄板形成碎片云的过程进行了数值模拟,得到了弹坑直径、外泡碎片云和内核碎片云的形状、分布,并与使用传统SPH方法、自适应光滑粒子流体动力学(ASPH)方法的模拟结果进行对比,结果显示:新方法在内核碎片云形状和分布上计算结果更加准确.同时对Whipple屏超高速碰撞问题进行了研究,分析了不同撞击速度下防护屏弹坑尺寸及舱壁损伤特性等特性,计算结果与实验吻合较好且符合Whipple防护结构的典型撞击极限曲线.%Based on the kinetic theory of granular flow (pseudo-fluid model),a new Smoothed Particle Hydrodynamics (SPH) algorithm suited for hyper velocity collision was presented in this paper.The damaged debris of the hyper velocity impact was equated with the pseudo-fluid and the effects of the debris' interaction and the effects of the gas on the formation process of the debris cloud were investigated.The new SPH algorithm was employed to simulate the 3D hyper velocity impact of an alloy projectile on thin target plates,and the numerical results of crater diameters,the structure and morphology characteristics of the debris cloud and the core debris cloud's shape and distribution were in good agreement with the experimental results.Compared with the simulations of the standard SPH and ASPH,the simulation of the new algorithm is more accurate in the core debris cloud's characteristics.Meanwhile,the hyper velocity impact of the Whipple shield problem was also simulated at different impact velocities.It was found that the crater diameters and the damage characteristics of the rear walls agree well with the experimental results,and that the simulation results are consistent with the typical ballistic limit curve of a Whipple shielding structure.