Mechanical Analysis of the Three-dimensional Deformation Shape Ratio of Spacer Knitted Fabrics under Uniaxial Tension

Spacer fabrics are three-dimensional textiles that are composed of two layers of separate fabric by interlocking threads. The special properties of these fabrics have made them widely used in the textile industry. In this study, the deformation of warp knitted spacer fabrics as an orthotropic structure under uniaxial tension is investigated. Samples are knitted with different bonding yarn angles and thicknesses. Uniaxial tension was performed for each sample in weft and warp directions with five repititions. Poisson's ratio measures the strain ratio of tensile and perpendicular directions, but shape ratio of threedimensional shape measures lateral area changes to volume. The Poisson’s ratio and shape ratio were calculated by measuring the square drawn on the fabrics. The results show that, in different samples, the shape ratio was more consistent with the reciprocal Maxwell’s theorem. Therefore, it better describes the deformation of the fabric under uniaxial tension