压环对爆炸成型弹丸成型影响的高精度仿真分析

The pressing ring is an indispensable part of an explosively formed projectile (EFP) charge structure for fastening the liner on the charge. A typical EFP charge structure with a copper spherical segment liner is adopted to study the influence of pressing ring on the EFP formed by the liner during explosion. The Influence of pressing ring on EFP forming properties is modeled and simulated using 3D dynamic finite element software, including Lagrange algorithm, arbitrary Lagrangian-Eeulerian (ALE) algorithm, smoothed particle hydrodynamics (SPH) method, and finite element method and smooth particle hydrodynamics (FEM-SPH) adaptive coupling algorithm. The EFP's velocity and shape characteristics calculated by each algorithm are compared with the EFP images captured by pulse X-ray photography, and the FEM-SPH algorithm is used to obtain the high precision simulation results of EFP formation. On this basis, for the basic EFP charge structure with mass ratio of pressing ring to liner M_R / M_L≤0. 2, the influences of the pressing ring's rectangular and non-rectangular parameters (axial and radial thicknesses, and sectional shape) and the materials of pressing ring on the EFP's initial velocity, mass conversion ratio, aspect ratio, and aerodynamic characteristics (compactness and windward area) parameters are simulated and calculated. Results show that the influences of axial and radial thicknesses and material parameters on the initial velocity of EFP is within 3%. The mass conversion ratio of EFP gradually decreases (up to 12. 6%), the aspect ratio of EFP shows a gradually decreasing trend (with maximum reduction of 19. 2%), and the compactness of of EFP with pressing ring is increased by 32. 6% compared with the case without a ring. The upwind area shows a decreasing trend, indicating that the increase of ring weight is beneficial to the formation of EFP and thus decreases its upwind resistance. The results of this study provide guidance for the optimal design of EFP charge structure.