Interfacial Bonding Strength Effects on Impact Response of UD-structured UHMWPE Fiber Soft Target Plate

To investigate the impact response of interfacial bonding strength on ultra-high molecular weight polyethylene (UHMWPE) fiber soft target plate, this study prepared 6UD structural sheets with varying interfacial bonding strengths by adjusting the adhesive formulation. These sheets were fabricated into UHMWPE fiber soft target plates with identical areal densities. Ballistic penetration tests employing 1.1 g wedge-shaped fragments were conducted, followed by comprehensive damage morphology and anti-penetration performance analysis. Combined with the LS-DYNA simulation software, the 6UD structural sheets were subdivided into three 2UD units, and the TIEBREAK contact method was introduced to simulate the difference in interfacial bond strength between the 2UD units. The velocity attenuation patterns of the fragments, the evolution of delamination zones, and the damage morphology of the rear-side projectile holes were analyzed across different models. The results revealed that the target plate with lower bonding strength was likelier to have extensive projectile holes and fiber debonding. At similar impact velocities, the total damage area of projectile holes in targets with different interfacial bonding strengths was comparable. The simulation results demonstrated that increasing interfacial bonding strength significantly enhances the targets' energy absorption capacity and ballistic limit velocity. In the early stages of penetration, interfacial bonding strength had minimal influence on shear failure. In contrast, in later stages, increased bonding strength played a notable role in energy dissipation and damage retardation. Furthermore, as bonding strength increased, the internal delamination zones expanded, while the projectile hole area on the rear-side layers of the same ply count decreased comparatively.