The ancient art of laying rope

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    Abstract

    We describe a geometrical property of helical structures and show how it accounts for the early art of rope-making. Helices have a maximum number of rotations that can be added to them — and it is shown that this is a geometrical feature, not a material property. This geometrical insight explains why nearly identically appearing ropes can be made from very different materials and it is also the reason behind the unyielding nature of ropes. Maximally rotated strands behave as zero-twist structures. Hence, under strain they neither rotate in one direction nor in the other. The necessity for the rope to be stretched while being laid, known from Egyptian tomb scenes, follows straightforwardly, as does the function of the top, an old tool for laying ropes.

    Original languageEnglish
    JournalEPL
    Volume93
    Issue number6
    Pages (from-to)60004
    ISSN0295-5075
    DOIs
    Publication statusPublished - 2011

    Keywords

    • Balance systems, tensile machines
    • General physics
    • Knot theory

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