Enhanced Bi-Layer Mosaic Armor: Experiments and Simulation

Three different alumina/aluminum bi-layer armors having different striking faces, i.e., monolithic alumina, mosaic alumina, and mosaic alumina enhanced by aluminum honeycomb, were fabricated and tested under the impact of the flat projectile. The ballistic performance of each armor type was also investigated using three-dimensional (3D) finite element (FE) simulations. Upon validating the FE simulation results with experimental measurements, the ballistic limit velocity and failure mechanisms for each type of armor, as well as the influence of ceramic tile size, impact position, border effect, and inter tile gap width were quantified. For the enhanced mosaic armor, the metallic honeycomb lattice performed as a cellular skeleton to confine the ceramic tiles and fragments, leading to enhanced ballistic resistance. Besides, the honeycomb enhanced mosaic armor was also found to have much improved multi-hit ballistic resistance in comparison with monolithic and mosaic alumina. The honeycomb preserved the structural integrity of the mosaic armor so that a high level of residual ballistic resistance remained even after impact. With the extended reliability calculation method, single shot ballistic data were used to estimate the performance of the honeycomb enhanced mosaic armor under multiple projectile impacts.