Enhancing ballistic performance: Effect of polyurea coating on backface deformation of UHMWPE laminates

Backface deformation (BFD) is a critical factor in evaluating the ballistic performance of ultra-high molecular weight polyethylene (UHMWPE) and similar protective materials, as excessive BFD can cause blunt force trauma. This study systematically explores how polyurea coatings influence BFD in UHMWPE laminates. Through a series of ballistic tests under varying conditions of polyurea thickness, coating position, and projectile velocity, we observed a significant reduction in BFDwith the application of polyurea coatings. Post-impact CT scans show the basic deformation pattern during the projectile penetration of the polyurea-coated UHMWPE laminate. Furthermore, a viscoelastic-plastic constitutive model for polyurea and a composite fabric plate model accounting for delamination were developed. The results of the finite element model (FEM) align well with the experimental findings, and demonstrate that the energy of the projectile during penetration is dissipated through shear fractures in the UHMWPE laminate and wave-like deformations toward the edges of the polyurea coating on the backface. The study provides new insights for the design of advanced bulletproof structures.