A novel plied yarn structure with negative Poisson’s ratio

This article presents an experimental and geometrical study of a novel kind of plied yarn structure with negative Poisson’s ratio (NPR). The deformation mechanism of the yarn structure formed with two stiff yarns and two soft yarns to achieve NPR behavior was firstly introduced. Based on the proposed yarn structure, four kinds of yarn samples were then fabricated with two kinds of stiff yarns and two types of soft yarns and tested under the axial extension to verify their auxetic or NPR effect. A geometric analysis was finally conducted to theoretically calculate the Poisson’s ratio of the yarn structure and compared with the experimental results. The study shows that the proposed yarn structure has obvious NPR effect and the geometrical analysis can well predict its Poisson’s ratio in the higher axial strain range. It is expected that this study could promote further development of auxetic textiles with unusual behavior.