Development of Johnson Holmquist model to simulate the impact of airborne projectiles on concrete structures

In this study, the damage behavior of concrete under projectile impact is investigated. Thus, Johnson Holmquist brittle damage model, which is widely used to model penetration phenomenon, is chosen as the basic model. In order to more accurately predict the behavior of the material, a modified model is proposed by considering the new relationship for the effect of rate on the strength of the basic structural model. In the first step, the concepts of the basic model are expressed. Then, the formulation of the damage model is extracted and algorithm of the model for numerical simulation to solve it are presented. In order to implement and validate the algorithm, a subroutine is written in Fortran programming language based on the finite element method to simulate the damage process. In the following, using the developed model, the impact of the projectile on reinforced concrete is investigated. The model is verified by comparing the numerical and experimental results in the literatures. Numerical simulations using the proposed model show a good compatibility between simplicity and accuracy for calculations of concrete slabs under the impact of airborne projectile.