Modeling and simulation of the effects of steel casing confinements on formation of explosively formed projectile

LS-DYNA software is used to model and simulate the effects of thickness and length of steel casing on the forming status of EFP specifically, and then a theoretical model is established to explain the forming mechanism and calculate the velocity of EFP. The following conclusion can be obtained. (1) The thicker steel cased charge can provide more impulse to the liner in EFP’s forming process. A formula of f(M/C) is fitted to estimate the steel casing effect on the velocity of EFP; (2)In order to get an EFP with higher solidity it is not necessary for the casing to fully cover the liner and charge, and when L_C/L₀ reaches to 35%, the obtained value of η can be as much as that when the casing fully cover the liner and charge with acceptable velocity range. And 65% of the casing mass can be lightened to reduce the weight of EFP charge structure; (3) A theoretical model to calculate the velocity of cased EFP based on the theory of instantaneous detonation is put forward to explain the mechanism of EFP’s forming process and calculate the velocity of EFP. The research results are significant in the design of light weight EFP warhead, and the theoretical model is easy and convenient of calculate the velocity of EFP with different steel cased charge structure, which can be used to provide reference for researchers in the design of EFP.