Effect of CRH Value on Damage Resistance of Aluminum Plate Under Bullet Impact

Ballistic performance of ductile targets is the most important factor for the safety of defense/protective structures such as shelters for armed conflict, bunkers for military liveware etc. In the present study, a three-dimensional numerical simulation is carried out using ABAQUS to study the effects of caliber radius head (CRH) value on the ballistic resistance of aluminum plates under normal bullet impact. The Johnson-Cock (JC) constitutive model was used to carry out the numerical simulations. The monolithic AA-7075 target of uniform thickness having size 100 × 100 mm were impacted by two different bullets with CRH value 1.0 and 2.5. The weight and radius of the bullet body were kept identical in all the simulations. The target plate was restrained from all four sides. The impact velocity of the bullet varied from 0.65 to 1.5 km/sec and the response of the target i.e., energy dissipation, damage, reaction force, etc. were obtained and compared. For a given impact velocity, the residual velocity of the projectile with CRH 1.0 was noticed higher than that for the projectile with CRH 2.5. In general, the reaction and energy absorption of the plate was noticed smaller against the projectile with CRH 2.5 when the impact velocity was closer to the ballistic limit. Projectile with CRH 1.0 and CRH 2.5 failed the ductile target through enlargement of the hole. The ballistic impact was critical in terms of hole enlargement and failure mode for a projectile with CRH 1.0 because of the sharper nose and smaller contact area and also longer ballistic length.