  Cotton threads and fabrics are the most used textile materials and have
garnered widespread interest for smart textiles to capture human-centered
cyber-physical and human-health-related bioanalytical data. Cotton threads are
sewn (manually or digitally) into fabrics to achieve functional and fashion
stitches that soften or stiffen the base fabric. There has been limited
investigation into the influence of a single stitch on the mechanical
properties of knitted cotton fabric. Such understanding may become critical to
producing optimized textile-based composites/smart materials involving sewing
operations. While stitching operations are investigated in numerous ways to
produce a range of smart wearables, herein, we demonstrate the rheological
modification of base cotton fabric induced by two types of singular stitches
(straight and zigzag). We have sewn simple straight and zigzag cotton stitches
to investigate the rheological modification of the base cotton fabrics.
Uniaxial stress-strain experimental data, combined with constitutive modeling
(i.e., three-network model, TNM) obtained from the calibration software
(MCalibration), revealed the feasibility of a data-driven approach to
investigate the rheological parameters. Our experimental analyses, combined
with the calibrated data, suggest a 99.99% confidence in assessing the
influence of a single stitch on knitted cotton fabrics. We have also used
distributed strain energy to analyze the mechanics and failure of the base and
stitched fabrics. Our study may enable the design and study of integrating
smart threads in cotton fabrics to produce smart wearables, e-textile,
biomedical and e-fashion textiles.
