Ballistic performance of UHMWPE fiber laminates with pre-formed holes

Abstract

Understanding how previous ballistic impacts affect the subsequent penetration resistance of ultra-high molecular weight polyethylene (UHMWPE) fiber laminates is crucial for their application in multi-hit scenarios. In order to investigate the effect of fiber fracture, a systematic examination of the ballistic performance of UHMWPE laminates with pre-formed holes is conducted through a combined experimental and numerical approach. Penetration resistance, dynamic penetration process, and deformation/failure modes of laminates with different configurations of pre-formed holes are tested and compared. A full three-dimensional finite element model is established, and a continuum homogenized model is utilized to simulate the laminate. The effectiveness of numerical model is validated by achieving a reasonable agreement between predictions and measurements. The presence of a single pre-formed hole will change the severity of delamination and result in tear failures, while it has minimal effect on penetration resistance until the spacing distance reaches 10 mm. When spacing distance remains the same, the change in orientation of a single pre-formed hole has little influence on the velocity history. Further, an enhancement in ballistic performance is observed when the number of pre-formed holes is increased to four, due mainly to the significant pull-in at the edge of pre-formed hole and the released fiber tensile stresses. The results of this study are valuable for comprehending the ballistic performance of UHMWPE laminate when subjected to multiple projectile impacts and have practical implications for the design of advanced protective systems.