Influence of the Medium and Structural Parameters on the Formation Effect of Linear Explosively Formed Projectiles

Abstract The linear explosively formed projectile (LEFP) is a special type of linear shaped charge (LSC) and is developed on the basis of the explosively formed projectile. Known for their excellent penetration performance and directional destruction capacity, LEFPs are widely utilized in explosion dismantlement, petroleum exploration, concrete crushing, metal cutting, and penetrator interception. LEFPs can also induce multimode damage—combining penetrator impact, shock waves, and bubble effects—during underwater detonations. Thus, they are employed in applications including subsea pipeline disruption and effective neutralization of underwater vehicles. Adequate formation effect is a criterion for a desirable penetration performance of shaped charges. Therefore, investigating the formation characteristics of LEFPs in different media and optimizing the structural parameters are important tasks. In this study, the arbitrary Lagrangian—Eulerian (ALE) method is adopted for numerical simulation, and the efficacy of the ALE method is verified by the consistency between numerical and experimental results. Then, the formation effects of LEFPs in pure air medium, water medium, and water with air cavity are investigated separately. The results show that the stabilized velocity of the penetrator in air is 1 355 m/s, while the velocity is only 423.6 m/s in water. Furthermore, the liner cannot be completely closed in water and cannot form a slender penetrator as in air. After the addition of the air cavity, the stabilized velocity of the penetrator increases to 966.6 m/s, and its morphology is significantly enhanced. Moreover, explosive material, liner material, and liner thickness are chosen as the primary factors for orthogonal optimization. The optimized factor combination is RDX—Copper—1 mm. The peak velocity of the penetrator, the velocity before penetration, the velocity after penetration, and the length of penetration increase by 50.8%, 44.9%, 26%, and 10.3%, respectively.