Knit mechanics, from yarn to garment

Knitted fabrics owe their stretch, recovery, and comfort to yarn-level mechanics that industrial practice still navigates by trial and error. We built a multi-level framework that starts from measured, anisotropic yarn behavior, resolves whole stitches in a volumetric finite element model, and then compresses what those simulations know into a three-parameter strain-energy surrogate that runs in minutes inside commercial tools. Validated across stitch lengths, patterns, and yarns, the framework extends to heterogeneous fabrics, where regions of different knits behave like springs in series and parallel. We used it to design a single-piece compression sleeve whose pattern varies along the arm so the pressure it applies does not.