Superelastic Helical Auxetic Structures with High Values of Poisson's Ratio

This paper introduces a novel superelastic shape memory alloy used yarn structure derived from the helical auxetic yarn (HAY) to obtain more stable structures and high values of poisson's ratio. The geometry of structure is defined and producing process described. A range of structures have been manufactured that vary the geometric parametre of structure. An experimental test bench has been set up and a systematic study has been completed to evaluate the effect on the auxetic behaviour of the geometry. Superelastic wrap wires were spun around the rubber core filament in same helical angel but different diameter ratio. Experimental results showed that the structure expanded transversely under tension and existed high negative Poisson's ratio values. Combination of superelastic and auxetic behaviours in textile structure can be useful in many applications, especially in medical and technical textiles applications.