A Modified Analytical Model for Analysis of Perforation of Projectile into Ceramic Composite Targets

In this paper, based on Woodward model(1), an analytical model has been developed for perforation of projectile into ceramic co mposites targets. In the new model, contribution of different phases of projectile during perforation (erosion, mushrooming and rigid phase), modificat ion of semi-angle of ceramic cone during perforation process, modification of the shape of the nose of projectile and changes in yield strength of ceramic during perforation are considered. The ballistic limit and residual velocity of projectile by presented model have a good agreement with experimental and other theoretical results of other researchers. Ceramic materials are widely used in armour systems as well as aircraft structures and military vehicles fo r the advantages of low density, high compressive strength, hardness and heat resistance. Response of ceramics to projectile impact and other types of high-speed loading conditions is an important issue for these applications. Ballistic performance of many types of ceramics was investigated in many experimental, theoretical and nu merical studies. A review of penetration/perforation process of ceramic targets can be found in(2,3,4). A great amount of these studies regarding ceramic targets subjected to high velocity impact investigate the behaviour of materials under impact load. The ceramic destroys the projectile t ip, slows it down, and distributes the load over a large area of the back-up plate. The back-up plate supports the ceramic and brings the comminuted ceramic and projectile to rest. The back-up plate material is selected on the basis of structural, ballistic, and weight considerations. Kevlar, fib reglass, spectra, and alu miniu m are most co mmonly used as the backing material. The mechanical properties of a ceramic determine its ballistic efficiency. The hardness of the ceramic causes the erosion and disintegration of the projectile, thus, preventing further penetration. The armour plate is exposed to very high bending stresses; hence, the ceramic must have high flexural and tensile strength. If the fracture toughness of the ceramic is too low, the crack propagation might be too severe after the impact wh ich could