Single‐ and Double‐Layered Bistretch Auxetic Woven Fabrics Made of Nonauxetic Yarns Based on Foldable Geometries

Auxetic fabrics made of nonauxetic yarns have gained increasing interest of textile scientists. Most recently, single‐layered bistretch auxetic woven fabrics made of nonauxetic yarns based on parallel in‐phase zigzag foldable geometry have been reported to have auxetic behavior when stretched along both principal directions. It is also reported that this geometry can possibly be realized into double‐layered woven fabrics. In addition, it is suggested that the phenomenon of differential shrinkage can be exploited to realize another variation of foldable geometry such as out‐of‐phase zigzag foldable structures into woven fabrics. Therefore, herein, two possibilities aimed to be explored are double‐layered auxetic woven fabric based on parallel in‐phase zigzag foldable geometry and single‐layered fabrics based on out‐of‐phase zigzag foldable geometry that are developed using the phenomenon of differential shrinkage to realize these geometries into the woven fabric structures. Five different auxetic woven fabric samples are fabricated using elastic and nonelastic yarns on a conventional weaving machine and tested along two principal directions. The testing results show that all the developed fabrics have auxetic behavior in both principal directions, and the placement of weaves and weft yarn arrangements has an obvious effect. The development of double‐layered and single‐layered auxetic woven fabric based on parallel in‐phase zigzag foldable geometry and out‐of‐phase zigzag foldable geometry, respectively, through the creation of phenomenon of differential shrinkage within the unit cell of fabric structure, is presented. The resultant fabrics show a negative Poisson's ratio over a larger range of tensile strain when stretched in both principle directions.