Advanced Simulation of Small-Arms-Class Ballistic Impact on Layered UHPC-FRC Protective Panels Using ANSYS Explicit Dynamics

This study presents a comparative numerical framework for evaluating the ballistic response of layered ultra-high-performance concrete (UHPC) and fiber-reinforced concrete (FRC) protective panels under small-arms class impact loading using ANSYS Explicit Dynamics. The Riedel-Hiermaier-Thoma (RHT) constitutive model was employed to capture strain-rate sensitivity, pressure-dependent strength, and progressive damage evolution in cementitious materials. Three target configurations with identical total thickness (100 mm) were investigated: a layered UHPC-FRC panel, a monolithic UHPC panel, and a monolithic normal-strength concrete (NSC) panel. Simulations were performed for projectile velocities ranging from 700 to 900 m/s using a rigid Truncated-Conical steel penetrator. Comparative performance was assessed through penetration depth, rear-face deformation, normalized penetration ratio, and energy-based response metrics. The UHPC and layered configurations showed stable penetration depths of approximately 60 mm across the investigated velocity range, while NSC exhibited substantially deeper penetration up to 91 mm. Rear-face deformation in the layered panel remained significantly lower than in NSC, indicating improved damage confinement and structural integrity. Although all configurations dissipated more than 99.93% of the projectile kinetic energy, the results demonstrate that ballistic performance depends primarily on energy redistribution and damage localization rather than total kinetic energy loss alone. The study provides a reproducible computational framework for comparative assessment of layered concrete protective systems under high-strain-rate impact conditions.