Comparison of the Ballistic Performance of Kevlar and UHMWPE Helmets Using FEM

Abstract

This numerical study compares the ballistic performance of Kevlar and UHMWPE (Ultra-High Molecular Weight Polyethylene) helmets. Armor models were obtained from experimental, numerical, and analytical studies in the literature, as well as the mechanical properties of Kevlar and UHMWPE were also obtained from the literature. Ballistic limit studies were performed to verify the materials. The residual velocities of FSPs fired at Kevlar and UHMWPE plates were compared with experimental data in the literature for Kevlar and the error rate was found to be 4.64 %. The UHMWPE ballistic limit converged to the analytical model in the literature with an error rate of 1 %. After the validation of the models, the ballistic performance of the helmets was analysed according to the NIJ 0106.01 standard. The pressure changes, pressure distributions, and positions of Kevlar and UHMWPE helmets under ballistic impact are shown. In addition, composite damages and Back Face Deformations (BFD) of the helmets were calculated. Kevlar ballistic helmet BFD value was 16.9 mm, while UHMWPE ballistic helmet BFD value was 18.8 mm. Thus, the ballistic protection performance and ballistic impact mechanisms of the helmets were analysed. While both helmets were found to provide NIJ II level protection, the fibre and matrix damage in the Kevlar helmet was higher than those of the UHMWPE helmet, but the BFD causing trauma was lower than those of the UHMWPE helmet. However, when the density of the UHMWPE helmet is considered, it is effectively lighter than the Kevlar helmet. In this study, numerical models of Kevlar and UHMWPE helmets were introduced to the literature and a study comparing their ballistic protection effects was conducted and the results are intended to guide future designs.