Study on mass erosion of kinetic projectiles penetrating reinforced concrete

To address the challenge of predicting mass erosion during the penetration of kinetic projectiles into reinforced concrete, this paper proposes a coupled calculation method. This method is based on existing mass erosion theories regarding thermal melting stripping and thermal softening cutting, while simultaneously considering the shear-plastic hinge resistance encountered by the projectile during direct contact with the reinforcement. Solved via multi-scale discretization, this method discretizes the entire penetration process into microsecond-level steps (10−6 s) on a temporal scale and employs micro-scale grid division on the projectile surface layer on a spatial scale. The calculated results show good agreement with experimental data, with a deviation of 2.74% between the predicted and experimental penetration depths for reinforced concrete. The study finds that as the initial penetration velocity increases, the thermal melting mechanism dominates mass loss, although the proportion of mass loss induced by the cutting mechanism exhibits an increasing trend. The presence of reinforcement mitigates the total mass loss of the projectile during the penetration process. Furthermore, the proportions of cutting mass loss, melting mass loss, and total mass loss all demonstrate a decreasing trend as the projectile mass increases. Further analysis reveals the existence of critical thresholds for the projectile’s initial velocity and concrete strength concerning reinforcement protective efficacy; when both exceed these thresholds, the reinforcement’s contribution to the concrete’s anti-penetration protection becomes negligible. The coupled calculation method presented in this paper provides a design basis for optimizing reinforcement and enhancing cost-effectiveness.