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In this paper, the behavior of multi-layered ceramic armor and ceramic armor with ductile backing against armor piercing APM2 projectile has been considered numerically. Multi-layered armors in accordance with BR7 ballistic protection class should protect against AP 7.62-mm projectiles with impact velocity of 830m/s. Results show that unlike high strength steel, ceramic resists against initial penetration of brass jacket and lead filler and erodes them at initial stages. This enables higher resistance in ceramic armor with similar mass in comparison with the steel one. It is illustrated that ceramic armor with ductile backing beside above characteristics has the capability of bullet jacket strip and capturing brass jacket while the core penetrates through the armor. This characteristic is not observed in multi-layered ceramic armor without the backing plate. Ceramic armor with backing plate reduces projectile's exit velocity one ninth the residual velocity of multi-layered ceramic armor and one nineteenth the residual velocity of high strength steel armor with similar mass. Another point discussed in this paper is the effective ceramic mass resisting against the projectile. The more mass involved, the more ballistic resistance gained.

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In this paper, the behavior of multi-layered Alumina ceramic armor against high velocity projectile has been considered. Due to the conoid failure mechanism of ceramics under impact loadings, high compressive strength and erosive behavior of them against projectiles, specially ogive nosed ones, various incorporation of this material in modern armor applications is possible. Consideration of this behavior by means of different constitutive relations in detail, such as given by Johnson & Holmquist, one can design an armor with higher ballistic performance. In this study, "conoid fracture" behavior of "ceramic - elastomer" armor has been simulated in LS - Dyna with Johnson - Holmquist constitutive relation. As a result, the conoid failure of top layer ceramic causes the impact pressure to decrease in back layer, and consequently the epoxy interface transfers the pressure distribution between ceramic layers, causing growth and propagation of conoid failure thus distributing the pressure in larger area, finally resisting against projectile penetration in the armor. Application of this armor system for light-weight and heavy back layer-free purposes, would be of the highest priority against high velocity projectiles.