Performance of Concrete Target in Protective Structure Under Hypervelocity Ovoid Long-Rod Projectile Impact

The dynamic response and material failure of concrete under hypervelocity impact are critical for assessing the performance of protective structures. This study investigates the depth of penetration and damage mechanisms of concrete targets subjected to ovoid long-rod tungsten alloy projectiles at hypervelocity regimes ranging from 1000 m/s to 1600 m/s. Three numerical algorithms within LS-DYNA, the traditional Finite Element Method (FEM), fixed-coupling FEM-SPH, and adaptive FEM-SPH, were systematically evaluated and validated against experimental data and established empirical formulas. The results reveal a significant transition in algorithmic performance at hypervelocities compared to high-velocity regimes. The fixed-coupling FEM-SPH model demonstrates superior predictive accuracy in the 1000–1600 m/s range, with an average error of 5.6% and a maximum error of 10.4%, effectively capturing the near-rigid penetration characteristics and stable projectile morphology observed in experiments. In contrast, the adaptive FEM-SPH algorithm, which is typically robust at lower velocities, exhibited the lowest precision with an average error of 32.6% (maximum 36.6%), likely due to the instability of SPH conversion criteria under extreme strain rates. While traditional FEM remains the most computationally efficient, requiring only 14.6% of the processing time of the fixed-coupling model, it suffers from substantial deviations (average error of 29%) as the projectile transitions into semi-broken penetration modes with significant mass abrasion, which increased from 10% to 27% in the simulations. The comparative analysis reveals that numerical stress oscillations in traditional FEM and the limitations of current adaptive conversion criteria make fixed-coupling SPH formulations the most reliable scheme for hypervelocity long-rod penetration assessments. This study provides critical guidelines for selecting appropriate numerical schemes for extreme loading scenarios, balancing the requirements for physical fidelity, accuracy, and computational efficiency in protective structural design.