Creep and Anti‐Sag Behavior of Polyester Outer Shell Fabric for Bulletproof Jacket

ABSTRACT Creep of outer shell fabric (OSF) of the bulletproof jacket (BPJ) is an important factor for determining its sagging behavior, which is an important aspect of OSF that carries heavy armor panels (hard and soft armor). In the present study, various woven fabrics from polyester, nylon, and high tenacity (HT) polyester yarns are prepared with rib‐stop constructions and evaluated for their creep behavior. In comparison to other fabrics, the HT polyester fabric shows the best creep resistance properties (0% in warp and 1% in weft direction) even after 12 h of loading. It is concluded that the HT polyester fabric has excellent anti‐sag properties at three different loads (2, 3, and 4 kgf) and meets the mechanical performance of OSF of BPJ. The OSF made of HT polyester rip‐stop fabric can be an alternative material to existing nylon OSF, exhibiting excellent creep, sagging, and mechanical properties at a 25%–30% cheaper cost. The Findley Visco‐elastic model is employed to investigate the creep and anti‐sag behavior of the fabrics while subjected to a constant load for a prolonged duration. Long‐term creep simulation predicts that the HT polyester fabric can retain its structural integrity till 5 years under operational loads of 4 kgf, making it a highly durable and cost‐effective OSF alternative to nylon.