Influence of projectile and thickness on the ballistic behavior of aramid composites: Experimental and numerical study

Ballistic impact loading is one of the most critical conditions to which structures can be subjected, and the selection of materials to be used is of fundamental importance. Kevlar (R) is considered one of the most efficient fiber, offering high protection against fragmentation and ballistic threats with reduced weight and thickness. In this work, ballistic behavior of aramid/epoxy composites plates of various thicknesses produced by vacuum infusion and impacted by actual projectiles of different geometries were studied through experimental and numerical approach. An extended testing campaign to evaluate material behavior in different loading cases was essential for an accurate definition of the material model. Residual velocity of the projectiles and energy absorbed by the composites were measured during ballistic tests. The damage mechanisms caused by the impact of the projectiles were analyzed through photographic and X-ray images and compared with numerical results. The energy absorption capacity and damage mechanisms were found to be strongly affected by the thickness of the material. Numerical predictions were consistent with experimental results both in terms of residual velocity and damage morphology, and some disagreement was found when the impact velocity approached the ballistic limit. The developed numerical model was used to produce the ballistic curve for different combinations of plates and projectiles, allowing comparison of panel efficiency for different thicknesses.