To promote prevention must study the behavior of these structures in the case of accidents, as shocks to prolong the lifetime of the structures. To predict the dynamic behavior of structures under the impact effect, we addressed the dynamic problem as a modeling and a numerical resolution. Indeed, this work is part of the dynamic impact study on a cracked plate. Our choice focused on numerical simulations to examine the response of a cracked plate aluminum alloy impacted by a spherical projectile diameter of 40 mm. A comparison was made with the case of a healthy plate flawless dynamically biased in the same conditions.