Numerical simulation research on Fragmentation effect of hypervelocity impact of ellipsoid shaped projectile normally onto a thin plate

Projectile shape has a crucial influence on the fragmentation of projectile and target subjected to hypervelocity impact. However, most of analytic and empirical models for predicting fragmentation in hypervelocity impact were derived based on spherical projectile. This paper presents a work performed for characterizing fragmentation of aluminum thin plates due to normal incoming aluminum ellipsoid shaped projectile by utilizing smoothed particle hydrodynamics (SPH) methodology. In simulations, the masses of ellipsoid shaped projectiles were fixed as the same, while the aspect ratio was varying from 0.05 to 5, the impact velocity was limited in the range of 3km/s to 7km/s, and the impact attitude was limited in the normal case which the rotational axis of ellipsoid being perpendicular with the target surface. In the postprocess of simulations, critical fragmentation characteristics including the velocity of the leading edge and the expanding velocity of the fragments cloud, perforation hole size, mass and velocity of primary fragment were analysed, with varying impact condition parameters. Furthermore, empirical equations of some fragmentation characteristics were proposed, and the parameters included in the equations were fit with simulation data.