An investigation of the ballistic impact behavior of multi-layered armor structure

In this research, a multi-layered composite armor was introduced by combining ceramics, fiber-reinforced composite and metal alloy with the aim of making the armor capable of resisting ballistic impact. A model was developed in ABAQUS/Explicit to predict the impact performance of armor in different scenarios. A thinner version of the proposed structure was manufactured, and experiments were conducted. Data were collected and analyzed including initial and residual velocity and absorbed kinetic energy. The experiments and simulations showed similarities in how the materials response to the ballistic impact. It was found that the thickness of each component contributes to the total ballistic resistance of the whole structure. By putting 20 mm thick Boron carbide layer in front layer, armor structure can absorb more kinetic energy than having 10 mm thick Boron carbide front layer. The sequence order of layers also affected the protection of armor structure. If the front layer is Kevlar/epoxy, armor structure cannot withstand multi-hit attacks because of significant delamination in these layers. Also, the Boron carbide core that had Kevlar/epoxy layer in the front was more shattered than the Boron carbide front layer that had Kevlar/epoxy as the core layer. By applying cohesive layers between Kevlar/epoxy layers, the displacement of fibers in the bonded composite layers was equal to 68% of the displacement of fibers in the unbonded Kevlar/epoxy layers. Also, the multi-layer structure with bonded Kevlar/epoxy layers exerted more stress on projectile after impact compared to structure with unbonded Kevlar/epoxy layers.