The Al₂O₃ Effect on Kevlar Composite for Armor Applications: Prediction, Validation, and Simulation for Ballistic Impact Testing

In this research project, the investigation focuses on understanding functionally graded materials' ballistic impact behavior. Thus, the study compares two Kevlar composite materials: one regular that has no additions and one that uses Al₂O₃ as a secondary reinforcement with an increasing increment of 3% per layer to a maximum of 75%. Two composites, Kevlar composite material (KCM) and functionally graded Kevlar composite material (FGK), underwent Charpy testing and showed impact strengths from 30.5 to 40.2 kJ/m² and 39.3–52.5 kJ/m², respectively, with an improved average impact strength of 23.7%. The results show that the areal densities of KCM and FGK are 5.11 and 5.60 kJ/m², respectively, with a higher density of 8%. In addition, the characteristic impact strength values for both KCM and FGK are 36.4 and 47.8 kJ/m², respectively. Furthermore, the Weibull modulus values for KCM and FGK are 12.81 and 10.88, respectively. Tested samples were analyzed on a microlevel by the SEM observing the fractography of KCM and FGK to find that addition of Al₂O₃ increased bonding between fibers creating semi-bridge structures causing impact load energy to transfer efficiently. Hence, the study concluded from the impact test that the FGK material has higher impact resistance than KCM. Both composites have been ballistically tested and optically examined. Further analysis to confirm the findings has been investigated through the Ansys simulation of ballistic testing.