Three-dimensional narrow woven fabric with in-plane auxetic behavior

Different auxetic structures and auxetic phenomena are continuously explored by researchers in the field of textiles with enhanced properties for broader application areas. However, developing three-dimensional (3D) auxetic structures by using weaving technology is a real challenge compared to knitting and non-weaving techniques. This research work reports a novel approach to develop 3D woven structures with in-plane auxetic behavior. A conventional 3D multilayer orthogonal through-the-thickness structure was converted into a 3D auxetic woven structure. The structure was designed with three different yarn components to incorporate auxetic geometry. One type of yarn was used in the warp direction, while the other two-yarn systems, comprised of fine elastic yarn and coarse binding yarn, were used in the weft direction. The auxetic geometry achieved resembles the reentrant hexagon by the unusual arrangement of warp yarns. For an in-depth study of the structure, nine fabric samples were fabricated by using a conventional semi-automatic weaving machine with four different influencing parameters. The developed samples were then tested on a tensile testing machine to evaluate their mechanical and auxetic behavior. The results show that the 3D fabrics have a negative Poisson’s ratio (NPR) even at higher tensile strain and that the appropriate binding to the warp yarn diameter can produce a higher NPR. In addition, the repeat size of the elastic weft yarn, bending stiffness of the binding yarn, and stretch percentage of the elastic weft yarn can highly affect the NPR of the fabric. Furthermore, among all the 3D woven fabrics developed with different structural parameters, the maximum NPR achieved was –1.61.