modeling poisson’s ratio and tensile behavior of auxetic 4-plied yarn

Auxetic yarns, renowned for their unique capability to expand laterally when subjected to tensile loading, are gaining recognition as innovative and adaptable structural materials. these yarns hold significant promise across a wide range of applications, including the development of auxetic fabrics with enhanced properties, the reinforcement of composite materials for improved strength and durability, and the creation of advanced smart wearable sensors with heightened sensitivity and functionality. in this study, a comprehensive theoretical framework is introduced, consisting of a geometrical model to predict the poisson’s ratio and a mechanical model aimed at forecasting the stress-strain behavior of auxetic 4-plied yarns (a4py). the proposed models integrate key parameters, such as the radius of the components, their respective young’s modulus and poisson’s ratio, and the twist per meter of the yarn structure. rigorous validation against experimental data from previously published studies confirms the accuracy and reliability of these models in capturing both the poisson’s ratio and the stress-strain responses, aligning with observed experimental trends.