Velocity distribution of fragments resulted by explosion of a cylindrical shell charge on multi-spots eccentric initiation

To address the issue of the increase of the fragment velocity of an eccentric initiation warhead, we put forward the view that this increase was caused by the Mach overpressure formed by the detonation wave collision. We used the AUTODYN software to simulate the whole explosion process of the eccentric initiation warhead, from the radial expansion of the shell to the formation of the surface cracks, and eventually the formation of the fragments. We then compared the simulation result of the fragment velocity with the test data and found that they were in good agreement. Further we combined the simplified Whitham method with the Gurney equation to obtain the calculation method of the directional fragment velocity and directional area of the eccentric initiation warhead. We studied the selection criteria for the number of the initiation spot on the premise of maintaining the fragment velocity. The results show that through the multi-spot eccentric initiation, the velocity of the directional fragment increases by about 34%, and the directional area range is approximately 30°; the selection criteria of the number of initiation spot is associated with the shell length and the charge diameter. Our study can provide a reference for the engineering application of multi-spot initiation eccentric warhead.