Influence of ceramic properties on the ballistic performance of the hybrid ceramic–multi-layered UHMWPE composite armour

The present research involves studies of the influence of the physico-mechanical properties of the ceramics on the ballistic resistance of the new concept of the hybrid, ceramic–multi-layered UHMWPE composite armour developed using SiC and Al2O3 ceramics differing in thickness. Ballistic verification of new design of the ballistic composite armour was conducted in the scope of the protection against more than one shot (multi-hit) using 7.62 × 39 mm MSC and 5.56 × 45 mm SS109 ammunition. Tests of physico-mechanical properties, covering the determination of density, acoustic impedance, Young’s modulus, hardness, and resistance to brittle fracture, were conducted for the ceramic materials. Obtained results show that the ballistic behaviour of the testing system based on ceramic tiles being made of the same materials (SiC or Al2O3) of the different thicknesses does not directly correlate with the hardness, brittle fracturing, or Young’s modulus of ceramics. For ceramic plates of the same thickness being made of different materials in chemical terms, performed studies have shown that the ballistic resistance of the testing system does not only depend on acoustic impedance of ceramic plates, which should be as similar as possible to the acoustic impedance of the backing material in the ballistic armour, but also the resistance to brittle fracturing K1c is an important parameter of the ceramic plates entering the composition of the armour, and it should be as high as possible. Only the combination of these two properties yields the best ballistic protection of the armour when testing using the multi-hit procedure with the use of 7.62 × 39 mm MSC and 5.56 × 45 mm SS 109 ammunition.