Table I provides more detailed information about the specifications of ropes made of different fiber types.
Single Yarns and Helix Model As mentioned above, the fibers in a rope are
twisted to various degrees to maintain the structural integrity, among other things. For filament yarns, the fiber arrangement in the structure is closer to the so-called idealized helical structures according to the description of Hearle et al
: “The yarn is assumed to be circular in cross section, and composed of a series of concentric cylinders of differing radii. Each fiber follows a uniform helical path around the concentric cylinders, so that its distance from the yarn axis remains constant. A fiber at the center will follow the straight line of the yarn axis; but, going out from the center, the helix angle gradually increases, since the number of turns of twist per unit length remains constant in all the layers. The density of packing of fibers in the yarn remains constant throughout the model; and the structure is assumed to be made of purposes lies in the requirement in durability, load-carrying capacity, and other physical, chemical, or service-related properties. Another distinction is that the majority of modern industrial yarns are often made of filament instead of staple fibers.
The mechanics of twisted fibrous structures is such a classic topic in textile science that there have been several books or monographs devoted to it.
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It is therefore not our purpose to provide all the detailed treatment on related topics. Rather, we list the major important issues and contributors in the area, the current status of the fields, and more importantly, stress, whenever possible, the issues or problems that have yet to be solved.