Top Down Modeling of Complex Knit Structures: Beyond Jersey Knits*

Modeling of knit textiles is popular in fields such as mechanical engineering and physics, where researchers are working to understand effects of yarn and loop geometries on fabric properties. Often, this can be computationally expensive, allowing only for modeling of planar fabrics such as jersey, made from all knit stitches. We see potential however, in complex self-folding structures, made with knit and purl stitches, as a means of engineering metamaterial textile properties. To aid in modeling of these structures, we have developed a topological framework for the knit structure using families of bicontinous surfaces which allow us to geometrically understand the physics of the characteristic boundary condition curling of jersey knits. We then consider complex self-folding as a result of competition between these boundaries, affected by contributing magnitudes of forces from course and wale directions. By characterizing these forces, we are developing a system of predicting this folding, through understanding of generalized behaviors that repeat regardless of material or machine. By studying interactions between segments of knit and purl stitches, rather than loops or yarns, we can more quickly understand this behavior, to engineer novel textile properties.