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).