Protective performance and dynamic behavior of composite body armor with shear stiffening gel as buffer material under ballistic impact

To solve the problem of insufficient protective performance of the existing body armor, an impact-resistant shear stiffening gel (SSG) with excellent flexibility and formability was innovatively used as buffer plate for body armor, and then combined with ultra-high molecular weight polyethylene (UHMWPE) ballistic panel to form a UHMWPE/SSG composite body armor. Based on the ballistic impact experiment and numerical simulation, the effect of buffer plate on the protective performance, and the dynamic behavior and protective mechanism of UHMWPE/SSG were analyzed systematically. The results indicated that the flexible SSG buffer plate could quickly stiffen under ballistic impact, thereby producing the strong "Jamming" effect to resist impact deformation and absorb impact energy. Moreover, the "Jamming" effect enhanced with the increase of impact load, and showed a distribution mode that weakened from the ballistic impact area to the periphery. Compared with traditional buffer materials, more impact energy was dispersed and absorbed by SSG, but less impact energy was transmitted to the human body. Therefore, the impact strength of UHMWPE/SSG on the human body and backface signature of human body were also significantly reduced (up to 50%), which showed that the composite body armor with SSG buffer material exhibited superior protective performance.