Formation and Penetration Damage Effects of Uniform-Thickness Liner TEFPs on Metal Targets

Abstract

This study investigates a toroidal explosively formed projectile (TEFP) warhead with an 88 mm charge diameter and uniform‑thickness liners. Normal penetration experiments on double‑layer Q235 steel targets were conducted at varying stand-off distances and liner thicknesses (3 mm and 4.5 mm), complemented by LS‑DYNA simulations to analyze TEFP formation and penetration behavior. The results indicate that increasing stand-off distance and liner thickness leads to a larger penetration hole diameter, but reduces both penetration capability and behind‑armor damage effectiveness, causing the failure mode at the hole bottom to transition from shear to tension. Microstructural observations reveal that grain evolution at the hole sidewalls involves dynamic recrystallization, severe elongation, and distorted deformation. Based on the impact angle θ, three penetration modes are identified: forward cutting (0° < θ ≤ 45°), quasi‑cutting (85° < θ ≤ 95°), and reverse cutting (95° < θ < 180°).