Calculation model of initial velocity field on multilayered spherical fragments warhead

In order to predict the initial velocity of multilayered spherical fragments warhead in detail, AUTODYN was utilized to simulate the process of explosively drive aimed at the typical warheads, filled with cylindrical charge and multilayered spherical fragments. It's found that velocities of fragments varied regularly in circumference on each layer and the mean velocity of inner fragments is bigger than that of outer fragments, especially in the case of more layers and less circumferential fragments. Then, a model was established by theoretical derivation based on momentum theorem and Gurney's hypothesis as well as the data from simulation. The model gives three types of velocity to characterize the initial velocity field. The three types of velocity is as follows: average initial velocity of fragment in any layer, maximum and minimum initial velocity of fragments. The results predicted by the model go well with test results.