Ballistic impact performance and blunt injury assessment of ceramic/ UHMWPE laminate composite body armor

Composite body armor made of brittle ceramic and tough laminate can protect human body from penetration while reducing weight. However, there is a lack of a simple and comprehensive method for assessing ballistic impact response and blunt injury. In this study, the three-dimensional Digital Image Correlation technique was used to investigate the back-face response of ceramic/ultra-high-molecular-weight-polyethylene laminate composite body armor impacted by a 7.62 mm rifle bullet. Blunt injury assessment was conducted by Bullet Coefficient (BC) and Abbreviated Injury Scale (AIS) criteria. Firstly, the ceramic tile exhibited transverse and radial cracks; the laminate showed thin layers separation, bullet holes and pits, kink, sheared, and torn morphology. Secondly, the bulge button face showed a transition from circular to rectangular shape, and the shear strain distribution exhibited an L-shaped pattern. Thirdly, at the moment of maximum bulge kinetic energy, approximately 8.73 % of bullet kinetic energy converted into total bulge kinetic energy, in which the x- and y-directional kinetic energy accounted for 29.66 %. Fourthly, the BC values decreased as the gap between armor and the human body increased, and the corresponding AIS decreased from 4 to 0. Finally, a Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM) coupled numerical model was applied to simulate the occurrence of ceramic cracks and laminate damage. This study proposed a quantitative evaluation of ballistic performance and blunt injury of body armor based on the back-face morphology. The results provide quantitative evidence to research the impact mechanism and offer methods for assessing human blunt injury behind the armor.