Ballistic Penetration Behaviours of Full-Width Weft Insertion Fabric Reinforced Flexible Composite

The demands of body armor on level of protection, weight, flexibility and comfort have always been difficult to strike an optimal balance. Most studies aim to promote the impact resistance of bulletproof materials, flexibility and comfort have not been sufficiently emphasized. Weft-knitted insertion fabric has excellent flexibility and body fitting ability, and the insertion yarns dissipate energy rapidly. In this paper, flexible composite laminates reinforced by aramid weft-knitted insertion fabrics (WKIFs) were developed. The ballistic performance was comprehensively studied based on the external damage appearance and internal damage image by high velocity impact tests and X-ray computed tomography. The finite element analysis was carried out to further explore the damage modes and failure mechanisms of composite materials. The results show that laminates reinforced by WKIFS have the potential to be applied in the bullet-proof field with the ballistic limit velocity of 365.31 m/s, 339.76 m/s and 338.29 m/s, respectively. For the laminates reinforced by weft-insertion fabrics, the front layers tend to be destroyed in shear, while the back layers are more probably to fail in tension. Further, the specific damage modes of the laminate were affected by the impact velocity of projectile. This study is of great significance to the development of flexible bullet-proof composite materials.