Dynamic Fracture Behavior of Layered Composite Under High Strain Rate Loading

Protecting military bunkers against projectile impact in the hilly region is of serious concern. These bunkers are generally constructed using locally available materials. Researchers are into developing more effective and efficient bunkers, made of reinforced concrete (RC), fiber-reinforced concrete (FRC), or layered composite which can provide improved resistance against enemy attacks. It has been observed that layered composite structures provide enhanced protection against impact loading as compared to RC and FRC. Therefore, this paper aims at investigating the dynamic fracture behavior of layered composite structures and their performance under projectile impact loading. In this study, the layered composite structure comprises of layers of soil, RCC panel, HR (hot rolled) sheet, and rubber. The composite target has been subjected to the projectile impact of 1.17 kg ogive-nose hard steel cylindrical projectile having 38.75 mm diameter. Additionally, a reinforced concrete mono-layer target of equivalent thickness has been considered for the performance evaluation and comparison with the multi-layer composite target. A computational framework has been developed to investigate the dynamic fracture behavior of the proposed composite structure. The mechanical performance in terms of the velocity profile of the projectile, residual velocity, penetration depth, crater diameter, and damage of different targets have been quantified through the numerical simulations. Furthermore, the fracture patterns have been evaluated and compared among different targets having varying thickness and material properties in each layer. It has been observed that multi-layered composite targets exhibit better penetration resistance in comparison with the mono-layer counterpart.