Terminal ballistic behavior of ceramic composite armors: study of ceramic cracking by a small caliber AP projectile

摘要

The aim of this study is to characterize the ballistic behavior of multilayered ceramic protection systems. The research work focuses on the understanding of the structural response of the composite target impacted by an armor piercing ammunition launched from standard light infantry guns which is represented by 7.62 x 51 mm AP NATO ammunition. Generally an extremely hard ceramic front plate is supported by one or several ductile backing plates. This study is focused on armor composed by ceramic and backed by an aluminum plate in order to absorb energy by plastic deformation and to support the ceramic plate during the impact. Numerical simulation by means of a hydro-code will contribute to understand the principal mechanisms of penetration and destruction of the armor, where a particular attention is drawn on the ceramic front layer. First tests have been performed in the ballistic laboratory in order to characterize the penetration of the ceramic front layer by a projectile. For this special case we chose ceramic tiles with sufficiently high thickness leading to complete projectile erosion on the ceramic front surface without any penetration (dwell). Ceramic cracking may occur by formation of a so-called Hertzian cone, cracking and fragmentation. Experimental and numerical investigations are further performed in order to understand this effect in detail and to identify the lower limits of the ceramic tile and the backing thicknesses. This study is an essential step towards significant armor weight saving without losing ballistic performance. Ballistic tests and numerical simulation are completed with dynamic tests like Hopkinson bars in order to characterize the behavior of each material and to make the implementation of correct parameters for constitutive relation.