What’s new in knitting, you might wonder after having wondered what’s new in sewing. Some physics is new, says this study:
“Programming mechanics in knitted materials, stitch by stitch,” Krishma Singal, Michael S. Dimitriyev, Sarah E. Gonzalez, A. Patrick Cachine, Sam Quinn, and Elisabetta A. Matsumoto, Nature Communications, vol. 15, 2024, article 2622. (Thanks to Nick Wills-Johnson for bringing this to our attention.) The authors report:
“Knitting turns yarn, a 1D material, into a 2D fabric that is flexible, durable, and can be patterned to adopt a wide range of 3D geometries. Like other mechanical metamaterials, the elasticity of knitted fabrics is an emergent property of the local stitch topology and pattern that cannot solely be attributed to the yarn itself…. However, predicting these mechanical properties based on the stitch type remains elusive. Here we untangle the relationship between changes in stitch topology and emergent elasticity in several types of knitted fabrics. We combine experiment and simulation to construct a constitutive model for the nonlinear bulk response of these fabrics. This model serves as a basis for composite fabrics with bespoke mechanical properties, which crucially do not depend on the constituent yarn.”