Damage Mechanism of UHMWPE Laminates under Multiple Projectile Impacts and the Influence of Interlayer Adhesion Performance

This study investigates the damage mechanisms of ultra-high molecular weight polyethylene (UHMWPE) laminates under multiple projectile impacts and examines the influence of interlayer adhesion performance on penetration resistance, based on X-ray computed tomography (CT) analysis and explicit dynamic finite element simulations. The results indicate that the non-perforating penetration process of multiple projectiles can be divided into three stages: the first stage is dominated by shear plugging; the second stage features shear-tensile failure accompanied by multilayer delamination; and the third stage is characterized by plastic deformation and rebound of the remaining structure, with tensile deformation and failure occurring primarily at the back face. These stages account for approximately 18, 44, and 38% of the total laminate thickness, respectively. Furthermore, when the UHMWPE laminate successfully resists perforation, the area severely damaged by the first projectile impact is contained within a circle of approximately 100 mm in diameter, centered at the point of impact. Due to damage accumulation, each subsequent projectile impact increases the affected damage area by approximately 10% compared to the previous one. Numerical simulation results reveal a negative correlation between the ballistic limit velocity of UHMWPE laminates and their interlayer adhesion performance. By reducing the interlayer bonding strength, the laminates exhibit enhanced energy absorption capacity and improved resistance to projectile penetration.