Theoretical and Experimental Estimation of the Stored Energy of Plain Knitted Fabrics Using Yarn Pullout Test

The yarn pullout test is a suitable method for investigating the internal mechanical properties of the fabric structure which is established during the weaving or knitting process. In this study, a theoretical model is presented to estimate the stored energy of plain-knitted fabrics which is determined using yarn pullout. The model can predict the stored energy in the fabric, based on the fabric dimensional properties of stitch length and yarn contact angle using force balance analysis. Moreover, in order to evaluate the suggested model, three types of plain-knitted fabric from cotton, cotton/polyester and cotton/nylon with three different stitch lengths were produced and subjected to pull-out tests. Comparison between experimental and theoretical results, demonstrates a reasonable prediction. The results show that the cotton/polyester fabric has the maximum stored energy, because of its higher yarn to yarn friction coefficient. It was also found that, the increase in fabric's loop length leads to a decrease in the fabric's stored energy.