Ballistic performance of flexible structures composed of UHMWPE fibers and airbag: Effects of the stacking order

A series of flexible structures incorporating an airbag and ultra-high molecular weight polyethylene (UHMWPE) fiber panels were designed as temporary architectures to offer both ballistic protective functions and lightweight constructions. Three primary structural configurations, monolithic structures (airbag or UHMWPE panel alone), bi-layer structures (airbag/ UHMWPE panel and UHMWPE panel/airbag), and sandwich structures (UHMWPE panel/airbag/ UHMWPE panel) were tested. A T12A carbon tool steel sphere with the diameter of 12.7 mm was utilized as the ballistic threat within an impact velocity range of 0-500 m/s. Investigations into the effect of stacking order on ballistic performance were carried out experimentally and numerically. The failure characteristics, ballistic limits, energy dissipations, impact processes and interaction effects of these structures are discussed. To facilitate the establishment of numerical models for impact analysis using ABAQUS, a material constitutive model of thermoplastic polyurethanes (TPU) including strain rate effect was developed. The numerical models of the monolithic single-sheet UHMWPE panel and airbag for impact analysis were subsequently verified by experiments in terms of impact processes and ballistic limits. The results reveal that arranging a few layers of UHMWPE panels in front of the airbag can improve the collapse ballistic limit while maintaining the failure ballistic limit. The inclusion of an airbag reduces the energy dissipation efficiency of composite structures. The potential to enhance ballistic protection through the combination of airbags and UHMWPE panels is highlighted. Stress dispersion and deformation restraint are identified as significant factors influencing the ballistic performance of the composite structures.