| Anti-missile warheads are mostly the directed fragmented warheads to use high-speed fragments to destroy incoming missiles.The fragments in the air are random.Therefore,the study of the effect of the fragmentation characteristics on the specific kinetic energy threshold for the impact of the explosive charge is the basis of the design of the fragmented warhead.In this paper,five kinds of fragments with different structures of cylindrical and hexagonal prism were selected,and the experiment of Comp B charge box with 10 mm thick Q235 shield was carried out.The speed range under experimental conditions was obtained.The maximum and minimum windward area of the five fragments were obtained by the theoretical calculation method.On the basis of this,the specific kinetic energy threshold of penetrating 10 mm thick Q235 shield Comp B charge was simulated by using LS-DYNA software under the maximum and minimum wind area.When the mass is the same,the upper and lower limits of the specific kinetic energy threshold with the six prism fragments are smaller than those of the cylindrical fragments.That is,under the same mass conditions,six prism fragments are easier to initiating shell Comp B.It is also found that the specific kinetic energy threshold of the fragment depends not only on the mass but also on the other characteristics such as the aspect ratio.The specific kinetic energy thresholds of the above fragments with 15°,30°,45° and 60° were simulated.Under the condition of the study,with the increase of the attitude angle,the specific kinetic energy threshold is increasing.That is,the greater the attitude angle with the same kind of fragments is,the more difficult it is to detonate the shell Comp B.Based on the aspect ratio of the fragments,the specific kinetic energy thresholds of the seven kinds of the aspect ratio were simulated with vertical penetration shield Comp B.The results show that with the increase of the aspect ratio of the fragments,the specific kinetic threshold of impact initiation is increasing.Under the same mass conditions,the vertical penetration of long rod fragments are not easy to initiating shell explosives charge.Under the same cross-sectional area conditions,there is no need to use large aspect ratio fragments.Based on the fragment structure,the specific kinetic energy thresholds of spherical,cylindrical,cubic,rectangular and hexagonal fragments were simulated with vertical penetration shell Comp B.The results show that the spherical fragments are the most difficult to initiating shell Comp B,followed by cylindrical fragments,hexagonal fragments,cuboid fragments and cube fragments.That is,under the same mass conditions,the cube fragments are easiest to initiating shell Comp B.Finally,the influence of the thickness of the shield layer on the specific kinetic energy threshold was studied.With the increase of the thickness of the shielding layer,the specific kinetic energy threshold of the fragment increases exponentially.The conclusion of the above research has great reference value to the structural design of the fragment warhead. |
