Characterising primary fragment in debris cloud formed by hypervelocity impact of spherical stainless steel projectile on thin steel plate

Hypervelocity impact of a projectile on a thin plate generates a debris clouds. Largest chunk (mass) of the projectile material (called primary fragment) in the cloud poses significant ballistic threat to subsequent structure. Primary fragment characteristics (mass, velocity and exit angle) are used in assessing subsequent structure damage potential. Non-dimensional empirical equations are proposed in this paper for estimation of these characteristics. A set of simulations has been carried out using smoothed particle hydrodynamics (SPH) technique of Autodyn. Two stage light gas gun test data has been compared for validation of simulation. Simulation results for spherical projectile made of stainless steel impacting mild steel plate with impact velocity of 2-4 km/s and obliquity of 0°-60° has been analysed. Constants and radicals of the proposed equations are determined by multi variable regression of the simulation data. Comparison of the simulation data with the proposed equations shows a very good fit.