Investigation On Ballistic Performances Of Thin Aluminum Plates Against Projectiles Impact

At present, it is frequently reported that the safety of civil aviation is endangered by foreign object impact. Therefore, it is key for the aircraft design and manufacturing departments to improve the ballistic performance of aircraft structure. The bullet penetrating metal plate experiments can provide basic experimental parameters for impact theory and failure mechanism. Meanwhile, the comparison between experiments and the analysis combined with finite element numerical simulation can provide reference for the aircraft design and manufacturing.Monolithic and double-layered targets made of 2A12-T4 & 7A04-T6 are penetrated by the blunt-nosed and ogival-nosed projectiles. Initial and residual velocities of the blunt-nosed and ogival-nosed projectiles are obtained from the experiments. Initial velocity-residual velocity curve, initial velocity-velocity variation curve and initial velocity-kinetic variation curve are simulated according to fitting formula proposed by Recht and Ipson and the corresponding ballistic limit is obtained. In addition, the failure mechanism of targets is analyzed with the stroked targets and projectiles. The penetration resistance characteristics of target plates against projectiles, the failure mode and the ballistic limit are revealed. Variation of velocity decreases with the increase of the initial speed of projectiles for blunt-nosed and ogival-nosed projectiles, and it is more obvious near the ballistic limit.Then, the penetration resisting performance of monolithic plates, double-layered plates with contact target type, and double-layered plates with air gap which are impacted by blunt-nosed and ogival-nosed projectiles are analyzed and failure form and mechanism are obtained. The results of the experiments show that the ballistic limit of monolithic plates is higher than that of the double-layered plates, and that the ballistic limit of contact type double-layered plates is higher than that of double-layered plates with air gap. In addition, the effects of different target structures on ballistic performance decrease with the increase of the projectile initial velocity.Finally, numerical simulation analysis for the above experiments by ABAQUS are carried out. The simulation results match with the results of experiments well, which can provide a basis for the design of protective structure.The findings of the research in this paper can provide significant experimental and theoretical ideas for the design of shield structures and understanding the ballistic performance of monolithic and multi-layered targets, and have some reference and guiding values in practice.