Experimental and numerical study on the flight and penetration properties of explosively-formed projectile

Three-dimensional numerical simulations and experiments were performed to examine the formation and spatial dispersion patterns of integral multiple explosively formed penetrators (MEFP) warhead with seven hemispherical liners. Numerical results had successfully described the formation process and distribution pattern of MEFP. A group of penetrators consisting of a central penetrator surrounded by 6 penetrators is formed during the formation process of MEFP and moves in the direction of aiming position. The maximum divergence angle of the surrounding penetrator group was 7.8°, and the damage area could reach 0.16 m 2 at 1.2 m. The laws of perforation dispersion patterns of MEFP were also obtained through a nonlinear fitting of the perforation information on the target at different standoffs. The terminal effects of the MEFP warhead were performed on three #45 steel targets with a dimension of 160cm  160cm  1.5cm at various standoffs (60, 80, and 120 cm). The simulation results were validated through penetration experiments at different standoffs. It has shown excellent agreement between simulation and experiment results.

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study on the Formation and Dispersion Patterns of Multiple Explosively Formed Penetrators

Liu

Long

et al. 2017

“…A complete EFP warhead consists of a metallic liner, high-energy explosive (HE), case, a slotted ring or sleeve and a detonator. After detonation, the dynamic interactions among the explosive products, case and liner present a challenging problem for designers to optimize EFP warhead [Wu et al,2007]. Johnson [1981,2006] firstly demonstrates the influence of geometrical parameters, including shell (liner) thickness, eccentric initiation and asymmetries in a shaped charge on the formation parameters of EFP.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response and Microstructure Evolution of Oxygen-Free High-Conductivity Copper Liner in Explosively Formed Projectile

Liu

Long

et al. 2017

The dynamic response and microstructure evolution of oxygen-free high-conductivity copper in a shaped charge liner are investigated through microstructural examination of a soft-recovery EFP. Adiabatic shear bands and voids which is the failure original of copper EFP can be observed in the rear part of the projectile. Numerical simulation results illustrate that the highest plastic strain reaches about 2.9 which can fully accommodate the grains deformation of copper EFP during the formation process at strain rates of the order of 10 4 s −1 . Theoretical calculation results indicate that the highest temperature increase of EFP caused by shock wave and plastic deformation can reach 747K, which is 0.55Tm (where Tm is the melting temperature of copper). The main body of the EFP undergoes completely dynamic recrystallisation, and the average size of the refined grains significantly decreases to approximately 10µm. A slight increase in grain size occurs mainly away from the center and extends towards the head and rear sections of the EFP. During the DRX process, the dislocation movement is believed to be the controlling mechanism significantly refining the microstructure.

“…Using LS-DYNA software, Li et al[2010] studies the problem of an annular multi-point initiation circuit applied to an EFP warhad with hemispherical liner, and the effects on the penetrator formation parameters by changing the initiation modes. In an EFP impact experiment presented by Wu et al[2007], a kind of arc-cone liner EFP warhead which can form a high-flying velocity and ideal dimensionless ratio of length and diameter penetrator is optimized and designed. According to the current research results, the hemispherical liner has been widely used in MEFP warhead.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study on the Dispersion Patterns and Penetration Properties of MEFP with Seven Arc-Cone Liners

Liu¹,

Long²,

Ji³

et al. 2017

A new MEFP warhead with seven arc-cone liners which can form 7,13 or 19 penetrators at different standoffs is designed. Dispersion patterns and penetration properties of MEFP are performed on five #45 steel targets of dimension 160cm x 160cm x 1.5cm at various standoffs (45cm, 60cm, 80cm, 120cm, 170cm). It reaches the conclusion that every surrounding liner is broken into three penetrators during the formation process of MEFP and a group of aimable penetrators consisting a central projectile surrounded by 18 penetrators is finally formed. Maximum divergence angle of surrounding penetrator is 9.8° and the damage area reaches 0.37m 2 at 1.7m. A nonlinear surface fitting about perforations information on the targets at different standoffs provides a method of predicting the dispersion patterns of MEFP. Once initiated, damage probability for defeating light armor of MEFP warhead with seven arc-cone liners is significantly improved and the results provide important reference to the design and optimization of MEFP warhead in engineering.