Numerical simulation of muzzle exit and separation process for sabot-guided projectiles at M > 1

Coupled fluid-structure simulations of muzzle exit and separation process for sabot-guided sub-caliber projectiles in supersonic flight are presented. In order to guarantee a separation without significant perturbations for the projectile aspects of both aerodynamics and structure loading have to be considered. Such simulations require sophisticated methods for fluid-structure interaction. A particular challenge results from the significant relative motion of sabot, projectile and muzzle. A two stage strategy based on a switch from an earth-based to a moving coordinate system is proposed. By this means, an investigation of the complete physical process for the separation including interactions with the barrel and the high pressure gas is possible. The AUTODYN software extended by in-house developed user-subroutines is applied for the simulations. Results for high-strength sabots of caliber 40 mm and different muzzle velocities are presented and compared with corresponding experimental data.