Failure and Damage Modelling of Alumina in Ceramic-Composite Ballistic Protection

The development of lightweight, high-performance structures for ballistic protection represents a crucial aspect of advanced defensive system design. The state of the art today involves the use of bi-layer protections, in which a high-hardness ceramic material is coupled with a more deformable material capable of dissipating residual energy (Kevlar, Dyneema). Understanding the interaction between these layers and their numerical modeling is essential to optimize the effectiveness of protections. This study focuses on the calibration of the Johnson-Holmquist II numerical model parameters for simulating the behavior of Alumina (Al2O3), used as the first layer of the protection. To characterize the material and understand its fracture mechanisms, both static (bending test) and dynamic (Hopkinson Bar test, drop test) laboratory experiments were conducted, followed by validation through FEM modeling (Abaqus). Based on the experimental data, a comparison was carried out among three initial parameter sets available in the literature, and the most suitable for the analyzed case was selected. Additionally, the presence of an elastomer interlayer between the ceramic and composite layers was preliminarily tested to investigate its effect on stress distribution. The results obtained provide the foundation for future studies on complete protection systems (ceramic-adhesive-composite backing) and for high-velocity impact tests using a gas gun.