Fig. 2: Experimental and simulated results of uniaxial stretching.
From: Programming mechanics in knitted materials, stitch by stitch
The stress-versus-strain relations for the four fabrics made from the acrylic yarn in the (a) x- and (b) y-directions. All of the data for each type of fabric is displayed by a different color: stockinette in blue, garter in orange, rib in green, and seed in purple. The experimental data is shown in the translucent regions where the width of the region is one standard deviation of the four experiment runs. The simulation data is shown with solid symbols. The solid curves are fits to the constitutive relations. This is a system where the linear response for each fabric is significantly different despite only small differences in the stitch configuration, whereas the nonlinear parts are quite similar. Experiments applying force in the x-direction show the extreme extensibility of the rib pattern compared with the other three. Garter and seed dominate in the y-direction. Note, the experimental measurements for seed fabric differ from that of simulations due to a compression-related buckling instability in the computation, investigated in Supplementary Note 4 and Supplementary Fig. 8. c Normalized rigidity plot of all fabric samples, where Yi is the Young’s modulus in the ith direction in N/mm (Supplementary Tables 10, 12, 14, 20), L is the length of yarn per stitch in mm (Supplementary Tables 2, 3, 6), A is the area of one stitch in mm2 (Supplementary Tables 5, 6), and B is the bending modulus in N mm2 (Supplementary Table 1). The colored ellipses represent one standard deviation for each of the four types of fabric and are oriented along the principal axes. The gray dashed line represents an isotropic mechanical response. The same analysis was conducted on the un-normalized rigidities, shown in Supplementary Fig. 11. Source data are provided as a Source Data file.
