Optimization of Multi-layered Composite Structures Against Impact Loading

Protection of military bunkers against projectile impact caused by arms or blast-induced fragments in the hilly region is of serious concern. Protective structures made up of homogeneous concrete or fiber-reinforced concrete might not be sufficient to resist repeated projectile impacts. Therefore, there is a need to develop and analyze functionally graded layered composite structures with varying material properties. Additionally, conducting experimental studies on such full-scale layered composite structures is extremely time-consuming and expensive. Analysis of such structures by developing a computational framework will provide realistic solutions. Therefore, the present study focuses on performing numerical simulations for providing feasible solutions for optimizing the configuration of the layered composite structure. In this research, the composite structure involves silty–sand soil, RCC panel, mild steel plate, and EPDM elastomer. The target has been subjected to the projectile impact of 1.62 kg ogive-nosed hard steel cylindrical projectile having a 52 mm diameter and length of 234 mm. Holmquist–Johnson–Cook model for concrete, elastoplastic model for reinforcement bars and mild steel, Mohr–Coulomb model for soil, Ogden model for EPDM elastomer, and Johnson–Cook plasticity model for projectile have been used in the numerical simulation. The effect of the strength of RCC and thickness of various layers of the target have been varied and compared to the penetration capability of the projectile. Based on the proposed study, an optimized configuration of the multilayered composite structure has been derived in terms of various output parameters such as deformation (penetration), stresses, and damage parameters.