Design and finite element study of Kevlar based combat helmet for protection against high-velocity impacts

High-velocity impact-resistant helmets are used by police forces, law enforcement and military personnel, firefighters, as well as civilians working in construction, manufacturing, mining and material handling industries among other sectors as protection against impact damage caused by projectiles of various shapes and sizes. In this study, an attempt was made to investigate the impact-resistance of fiber-reinforced polymer composite based helmets through finite element analysis. The composite helmets were modelled in different sacking sequences using bi-directional woven fabrics such as Kevlar-129 (K), 3 K-Carbon (C) and EC9-Glass (G) fabrics as reinforcements and an epoxy matrix formulation. Investigation was focused to study the high-velocity impact resistance and energy absorption performance of composite helmets in hybrid and non-hybrid stacking sequences such as KKK, KGK, KCK, KCG and GCK subjected to high-velocity impact simulations at 398 m.s⁻¹. It was observed that neat Kevlar and Kevlar-glass sandwich hybrid composite helmets withstood the projectile, while all other hybrid helmets were completely perforated during impact. It was also found that Kevlar-glass sandwich helmets offered cost savings of about 21% compared to neat Kevlar-epoxy composite. Hence Kevlar-glass sandwich composite can be used to develop protective helmets due to their attractive impact resistance properties and lower cost. The variation in helmet weight among all the considered composite material combinations was only about 5%.