Influence of repeat unit size on the auxetic effect of foldable weft knitted fabrics

Abstract

General phenomenon of engineering materials is to reduce the width when stretched. The auxetic materials expand in the lateral direction when stretched and contract when compressed, giving a negative Poisson’s ratio. This exceptional behaviour of auxetic materials offers great benefits such as enhanced fracture toughness, superior indentation resistance, and better energy and sound absorption. Auxetic knitted fabrics have a high potential to be employed in areas of tissue engineering, adaptive clothing, and various fashion applications. The inherent curly configuration of single jersey weft knitted fabrics makes it an ideal candidate for creating foldable auxetic fabric structures. Therefore, a foldable weft knitted structure is selected for further investigation. Various foldable knitted structures were developed by changing the repeat unit size and evaluated for the folding properties. The highest negative Poisson’s ratio reported was minus 0.73 from the 24x24 (courses x wales) repeat unit.