Abstract: In order to study the distribution of fragments of hypervelocity 93W projectile impacting on a steel plate target, the AUTODYN software is used to do the smoothed particle hydrodynamics simulation, and the GRAY solid-liquid phase equation of state is added as a user subroutine in the software. The hypervelocity impact process under the conditions of different impact velocities and body diameters was simulated, and the simulated results were verified by the experimental results. The distribution characteristics of mass, quantity, momentum, temperature and other parameters of the fragments were obtained based on the breadth-first search algorithm for fragments recognition. The study results show that the quantity and quality of fragments are mainly concentrated at the front part of fragment group, are less at its middle part, and are increased at its tail part. The big mass fragments are mainly concentrated at the front and tail parts of fragment group, and their lateral velocities are low. The front part of the fragment group has higher quality, and higher axial and lateral momenta, which represents the damage power of fragment group. High temperature fragments mainly distribute in the middle to front part of the fragments group, and there are many low temperature fragments at the front and tail part of the fragment group. The resultant velocity of high temperature fragments is above the medium velocity of all fragments, and the fragments with high resultant velocity are distributed in all temperature sections. A fragment group with more fragments and higher total mass can be produced by increasing the diameter of projectile than increasing the impact velocity. The change of diameter of projectile or impact velocity has a more significant effect on the front part of fragment group, so the damage power of fragment group can be effectively improved. Key

Key words: tungstehalloyprojectile, hypervelocityimpact, distributionoffragments, smoothedparticlehydrodynamics, GRAYequationofstate