Penetration resistance of reinforced concrete slab subjected to rigid projectile impact based on finite element and analytical models

The growing diversity of projectile shapes has significantly fueled research into the penetration resistance of reinforced concrete (RC) targets subjected to rigid projectile impact, with penetration depth emerging as a critical determinant. Accurate prediction of penetration depth is paramount for designing protective structures, yet this remains challenging due to the scarcity of strain rate dependent experimental data. This study bridges this gap through comprehensive finite element simulations, evaluating the penetration performance of 200 mm thick RC slab under normal impact by projectiles with a constant diameter of 25.3 mm. Strain rate dependent concrete strengths ranged from 20 to 135 MPa, and impact velocities spanned from 100 to 1000 m/s. An RC slab (675 × 675 × 200 mm) was modeled using 8-node hexahedral solid elements, with validated by comparing experimental and numerical results. Strain rate effect by concrete damage plasticity model based numerical simulations were conducted for projectiles with varying nose shapes (i.e., ogive, hemispherical and flat) as well as masses of 0.386, 0.771, and 1 kg. This study investigates the influence of projectile characteristics and target properties governing the penetration depth and the corresponding impact velocities. Results demonstrate that the penetration depth declines as the concrete strength escalates, with ogive-shaped projectiles consistently achieving a superior penetration. Furthermore, increased projectile mass and velocity markedly amplify the penetration depth, although higher-strength concrete exhibits stronger resistance. An analytical model, derived from the cavity expansion theory effectively quantifies the effects of these parameters, with an acceptable agreement observed between analytical and numerical results, underscoring its reliability and accuracy.