Numerical Simulation Study Of Dynamic Response Of Reinforced Concrete Under Different Impact Loads

Concrete is one of the materials commonly used in typical protective targets,and the dynamic response of concrete structures varies under different strain rate impact loads.The study of the mechanical response of concrete structures under different strain rate impact loads can help to improve the impact resistance of concrete structures and can also provide a reference for munitions to destroy concrete structure-like targets.In order to study the dynamic response of reinforced concrete structures under low and high velocity impacts,numerical simulations of typical reinforced concrete structures subjected to falling hammer impact and fragmentation penetration loads were conducted in ABAQUS and compared with the experimental results.The details and conclusions are as follows:(1)The secondary development of the classical concrete dynamic intrinsic model-HJC model was implemented in ABAQUS,and the VUMAT subroutine of the HJC model was written.Compression and tension tests were performed on individual units and compared with the calculation results of the embedded model,and the trends of the stress-strain curves were in good agreement.The peak compression stress difference is within 11%,indicating the correctness of the VUMAT subroutine written;(2)numerical simulation studies were conducted on reinforced concrete beams impacted by falling hammers from different heights,and the calculated peak impact force and mid-span deflection were in good agreement with the previous test results.Due to the nature of concrete compression resistance but not tensile resistance,the HJC model has limitations in predicting concrete damage,and in addition to the mid-span part,the reinforced concrete beam also has different degrees of damage areas on both sides,which is different from the experimental results.The effects of different fragment diameters,different placement of reinforcement and different impact points on the dynamic response of the reinforced concrete target were analyzed.The damage of the projectile face is proportional to the diameter of the fragment.The location of the reinforcement mainly influenced the damage of the bullet-face and the damage of the reinforcement laying surface,and the reinforcement suppressed the crack expansion and the expansion of the damage area.The damage area moved with the change of the spring-loaded point and was concentrated near the spring-loaded point,and the reinforcement effect of reinforcement crossover on the concrete structure was stronger than the case of single reinforcement.The numerical simulation results are in good agreement with the experimental results.The research content of this paper can provide some reference for improving the impact resistance of concrete structures and achieving efficient destruction of reinforced concrete structural targets by munitions.