In-Plane Deformation Behavior and the Open Area of Rotating Squares in an Auxetic Compound Fabric.

A conventional compound fabric was used to develop a modern, multifunctional material with an auxetic behaviour and a tailored open area for particle filtration. Such material was produced using traditional textile technology and laser cutting, to induce a rotating squares unit geometry. The behaviour was investigated of three different rotating unit cell sizes. The laser slit thickness and the length of the hinges were equal for all three-unit cells. The tensile properties, Poisson's ratio and auxetic behaviour of the tested samples were investigated, especially the influence of longitudinal displacement on the fabric's open area and the filtered particle sizes (average and maximum). Results show that the developed compound fabric possesses an average negative Poisson's ratio of up to -1, depending on the applied auxetic geometry. The larger rotating cell size samples offer a higher average negative Poisson's ratio and a higher breaking strength due to the induced slits. The findings highlight the usefulness of patterned cuts in conventional textile materials to develop advanced auxetic textile materials with tailored geometrical and mechanical properties.