Cutting resistance of flexible armour using multiple layers of triaxial kevlar fabric

The textiles capable of cutting resistance found applications in the industrial and military areas to construct flexible lightweight soft body armors. In the present work, a theoretical model to understand the mechanism of fabric cut resistance in a different direction for weft-knitted, triaxial, and multiple layers structures. An experimental study of cutting resistance force was done on weft-knitted fabric with Kevlar 29 triaxial fabrics in multiple layers structure to support derived mathematical model for the effect of multiple layers structure on their cutting force. The study examines specific cut resistance of the structure from four layers of Kevlar triaxial fabrics covered with knitted fabric on both sides. The angle of cutting force varied from 0°, 60°, and 90° with respect to the yarn inclination. Results show that the cutting force of the multilayer structure is linearly proportional to the number of Kevlar triaxial fabrics layers. The specific cut resistance value of the structure from four layers of Kevlar triaxial fabrics, covered with knitted fabric on both sides, reached 544, 435, and 326 (N/g/cm ² ) for cutting directions: angled 60°, vertical, and horizontal, respectively. In this work, the comparison between the triaxial fabric of high areal density and multiple layers of triaxial fabric with resultant same areal density indicates that a better specific cutting force was achieved in the first case. Furthermore, it investigated the relationship between triaxial surface density, the direction of cutting, and the number of triaxial fabric layers and discussed the optimum specific properties of the different structures.