Prediction Model for Missile Impact Performance of RC Targets with Enhanced Reinforcement Configurations

In order to protect the integrity of nuclear power plants and prevent the leakage of radioactive materials, nuclear containment structures are essential. For enhanced safety and integrity, these structures must be protected against the threat of missile impact, which necessitates the development of effective design methodologies and efficient mitigation strategies. The main objective of this study is to examine the possible mitigation techniques for nuclear containment structures that could be affected by missile impacts. The research explores the mitigation approaches for the missile impact on the reinforced concrete targets through a comprehensive numerical parametric study, carried out in Livermore LS-DYNA software. The parameters considered are (1) thickness of concrete (180 mm to 250 mm), (2) grade of concrete (30 MPa to 50 MPa), (3) reinforcement pattern [single mat reinforced concrete (SMRC), double mat reinforced concrete (DMRC), double mat shear reinforced concrete (DMSRC), single laced reinforced concrete (SLRC), and double laced reinforced concrete (DLRC)], and (4) placement of steel liner (with a liner thickness of 2.25 mm and 4.5 mm) at the distal face and the effect of nose shape (flat nose, hemispherical, and conical nose). The length of the missile was adjusted according to the shape of its nose while ensuring that the overall mass and diameter of the missile remain constant at 11.75 kg and 80 mm, respectively. The variations of penetration depth, residual velocity, and ballistic limit are studied. The following are observations from the parametric study: (1) the concrete grade affects the penetration and perforation but does not significantly improve the ballistic limit; (2) the ballistic limit was improved by increasing the thickness of the steel liner and concrete target; and (3) due to the concentration of forces in the smaller regions for conical nose impact (θ=15°), the penetration depth of concrete or residual velocity of the missile was increased compared to flat nose and hemispherical nose shape missiles.