Impact Mitigation in a Conico-Cylindrical Projectile During Sub-ordnance Velocity Impact

This work demonstrates effective impact load mitigation methods which can be used to provide protection of subsystem inside a conico-cylindrical projectiles during impact at sub-ordnance velocity ranges (25–500 m/s). The projectiles under a short duration impact with hard soil or concrete structure lead to large deformation due to high ‘g’ deceleration inside projectile subsystem. Typically, these projectiles contain sophisticated electronics packages and high energetic materials inside at different locations. Evidently, high ‘g’ deceleration loads can severely affect their intended function due to uncontrolled deformation mode. In view of this, present study investigates the energy mitigation effect in terms of pressure–time history of energetic material, deceleration of the projectiles, and critical parameters for detonation like energy fluence at various places inside projectile using finite element simulation in ANSYS/AUTODYN® using explicit dynamics approach. The respective methodology for energy absorption/dissipation by different materials deformation, use of collapsible rods and bimetallic rods inside cones were simulated and compared to enhance the crashworthiness of the projectile. Plastic deformation of collapsible and bi-metallic rods induces weak points by buckling and bending of rods, leading to higher energy dissipation, hence providing better and safer impact mitigation to protect projectile from damage due to accidental impact.