Optimization of adhesion performance of level IV ballistic body armor plates

The level IV ballistic body armor plate, providing protection against armor-piercing (M2 AP) rounds, consists of six layers for personnel safety and comfort. These layers include: the outer casing, soft surface, lamination surface, ceramic section, adhesive surface, and polyethylene section. The combination of these layers forms a multi-curved (multicurve) and monolithic (single-piece) level IV armor plate. For optimal ballistic performance, there should be no gaps between the layers. Therefore, the adhesive material and manufacturing method used during production play a critical role. In this study, ceramic and polyethylene-based materials used in the level IV ballistic body armor plate were combined into multi-curved (multicurve) and monolithic forms using three different types of ceramic plates (alumina, silicon carbide, boron carbide), three different manufacturing methods (pressing, hydraulic press, autoclave), and three different types of adhesives (cold bonding, epoxy, thermoplastic). The final products produced were subjected to ballistic testing according to the NIJ-0101.06 standard, with the aim of determining the most suitable adhesive type and manufacturing method. Alumina (Al2O3), silicon carbide (SiC), and boron carbide (B4C) were used as the ceramic plates, which are responsible for breaking the projectile's core and absorbing its energy, while polyethylene fabric was used as the support/holding plate, responsible for stopping the projectile's forward motion. A total of 43 level IV ballistic body armor plates were produced in this study. Based on the ballistic testing results, it was determined that the most suitable adhesive type among the three adhesives and manufacturing methods tested was thermoplastic adhesive, and the most suitable production method was the autoclave-based production method.