Phys. Rev. X (in the press); preprint at https://arxiv.org/abs/1801.08355

Being an ancient yet powerful technology, knitting has long been known for its broad utility in crafting beautiful structures with extreme three-dimensional flexibility. But the topological mechanics of these structures is not entirely understood. Now, Samuel Poincloux and colleagues have applied themselves to this industrially relevant gap in mechanical physics, delivering an insightful first-principles model for knitted threads.

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Maryana Lyubenko/Alamy Stock Photo

Knitting fabric in the so-called stockinette pattern (pictured), a structure described by an array of singly stitched unit cells, Poincloux et al. monitored the structures’ mechanical response under different loading cases. By comparing the results to theoretical predictions and achieving quantitative agreement, they demonstrated that the key factors of the model are the yarn’s bending energy and the conservation of its length, along with the topological constraints of the stitches. The model provides a theoretical basis for a technique that has so far been based on empirical knowledge. In doing so, it paves the way to harnessing knitting technology for next-generation smart materials.