Determining Pseudo Poisson's Ratio of Woven Fabric with a Digital Image Correlation Method

In this paper the determination of pseudo Poisson's ratio of woven fabric with a digital image correlation method is presented. Measurements were performed on three cotton woven fabric samples which were prepared according the standard ISO 13934-1:1999. The fabric sample was exposed to tensile loading of 1% strain on a tensile test machine. Testing was simultaneous recording with a digital video camera. These video recordings were afterwards processed in the MATLAB program and the pseudo Poisson's ratio determined according to the displacement in the x and y axis directions. The pseudo Poisson's ratio was determined for three woven fabrics in the warp and weft directions. The results of the investigation show that the values of the pseudo Poisson's ratio are in the range from 0.2 to 0.5, which agrees with results also found in the literature. According to the investigation it can be concluded that the value of the pseudo Poisson's ratio depends on the weave type and the number of yarns in the fabric. For woven fabric in plain weave a higher pseudo Poisson's ratio is determined (warp direction from 0.335 to 0.500, weft direction from 0.392 to 0.484). The pseudo Poisson's ratio for woven fabric in twill weave has values in the warp direction from 0.281 to 0.329, and in the weft direction from 0.183 to 0.214.