نوع مقاله : مقاله پژوهشی
1 عضو هیات علمی پژوهشگاه علوم و فنون هسته ای
2 کارشناسی ارشد مهندسی عمران- زلزله، موسسه آموزش عالی صدرالمتألهین
عنوان مقاله [English]
In this paper the nonlinear modeling of the projectile impact on special domed reinforced concrete structures is investigated. The projectile penetration in the structure is dependent on different conditions such as velocity and mass. Based on the finite element model created in the Autodyn software, the nonlinear behavior and the projectile penetration in the concrete shell of a dome-shaped structure with regard to the mass and velocity of the projectile and all contact behavior of concrete has been presented. The analysis method used has been defined in Lagrangian coordinates. The Johnson Cook Linear and RHT Concrete were used to model the material behavior for projectile and target respectively. Reinforcement has been simulated using a linear model of Johnson Cook too. Dimensional four-node axisymmetric elements were used in the software. Also the effect of various parameters on the depth of penetration of the projectile, such as velocity, bullet weight, multi-layer and reinforced concrete is being investigated and the results were presented. In this regard, the study of projectile velocity and mass and their impact on the depth of penetration will be discussed. First, the impact of a supersonic cruise missile with speed of 1620 kilometers per hour (Mach 4.6) on a target has been discussed. Subsequent analysis of the projectile weighing 900 kg (twice conventional warhead) impact on the target. Since the kinetic energy of the projectile is double the previous case, a good approximation can be assumed that two projectiles hit the structure. In the third analysis, it is assumed that the threat has a double-speed warhead with two and a half times mass. Based on results we found that the first and second structures still has the resistance, but against the third threat the structure has no longer resistance and the projectile passes through the target. At the end a sensitive analysis for mesh size has been performed and the effects on the results were presented.