Of all the twisted fibrous structures for industrial applications, ropes are probably the most complex in terms of structural compositions and application scenarios. Because ropes contain all forms of
PROPERTIES OF TWISTED STRUCTURES. II 611
Figure 1 A rope structure.
industrial twisted structures, in this article, they will be dealt with principally.
Materials Marine ropes are composed of millions of individ-
ual fibers twisted and combined into many levels of substructures such as yarn, plied yarn, rope yarn, and strand (Fig. 1). The levels of structure are dependent on the complexity of the rope geometry. However, in principle, at least three levels can be identified, i.e., fiber, yarn, and strand.
In natural fibers, manila and cotton are common materials for rope, and in synthetic materials, nylon, polyester, polypropylene, and recently, Aramid (Kevlart) fibers are all good candidates as rope-making fibers.