Knitted auxetic fabrics (AF) are in common practice but their stability and thickness are major problems in commercial applications. Therefore, a simple method of developing woven AF is proposed here. Differential shrinking property of different weaves is utilized to visualize auxetic honey comb geometry in fabric structure. Based on this fabric structure, auxeticity is induced in 2-D-woven fabric. AF is developed using conventional nonauxetic materials (i.e., cotton in warp and elastane [Lycra] yarn in the weft). Auxetic nature and auxetic structure in the fabric were characterized by microscope. Comfort properties (air permeability, thermal resistance, stiffness, and wicking) of AF were compared with conventional nonauxetic fabrics (NAF). Piezoresistive nature of conductive AF and NAF is also compared. AF showed superior comfort properties and higher sensitivity as compared to conventional NAF. Based on results, AF can be considered better replacement of conventional NAF in wearable and medical applications.

Auxetic materials are under great attention of researchers due to their excellent mechanical response under certain conditions. Previous works have been carried out in knitted or uni-stretch woven fabrics. In the present study, three-dimensional (3D) woven structures were produced and the effect of float length of ground weave and binding yarn on auxeticity of the fabric was investigated. Eight different 3D orthogonal woven structures/reinforcements were produced on rapier dobby loom by changing the float length in ground weave and binding yarns. Hand layup technique was used for composite fabrication, while green epoxy resin was used as a matrix. For investigating the auxeticity, 3D reinforcement samples were subjected to tensile loading and change in their thickness was measured. The results showed that 3D woven reinforcements with equal and maximum float length of ground weave and binding yarn showed greater auxetic behavior, because both weaves support each other and room for opening of structure increases. As the difference between the float length of ground weave and binding yarns increases, the auxeticity of reinforcement decreases because the ground weave and binding yarn cancel out the effect of each other. Moreover, the impact energy absorption of the developed composites was found to increase with the increase in float length, justifying that the structures are auxetic in nature.