Effect of Projectile Rotation on High-Velocity Impact Fracture

This study explores the effect of rotation of an ogival high-strength steel projectile on its fracture during high-velocity collision with a steel target of finite thickness. The considered range of impact angles is from 0° to 75°. The initial projectile velocity is 1000 m/s. The rate of projectile rotation about the longitudinal axis is varied from 0 to 10 000 rps. The behavior of the projectile and target materials is described by an elastic-plastic model. The limiting value of the plastic strain rate is used as a fracture criterion. Finite element simulation is carried out using an original algorithm and EFES 2.0 software package for modeling the fragmentation of interacting bodies with the formation of new contact and free surfaces, as well as erosion fracture of materials. The adequacy of the mathematical model and the numerical algorithm is confirmed by good agreement between experiment and simulation. The results obtained show that the projectile rotation has a significant effect on the fracture of interacting bodies and the projectile kinematics. It enhances the plastic deformation of the projectile in the contact area and erosion fracture, and increases the occurrence of a ricochet by reducing the impact angle. In the case of an oblique impact, with increasing impact angle α to 70°, the volume of the fragmented material (debris) of the head for both the rotating and nonrotating projectile increases, leading to a decrease in the kinetic energy of the projectile part that penetrates the target.