Effects of Bending Stiffness in Tow and Salvage Cables

The effects of the small amount of bending stiffness that a tow or salvage cable are known to possess are considered. The results show that there are significant differences in the states of stress of a cable without stiffness and a cable with a small amount of stiffness in the neighborhood of a concentrated loading such as that arising due to a fitting. Furthermore, the magnitude of these differences are independent of the amount of bending stiffness. It is the extent of the region of the cable over which these differences occur that diminishes as the bending stiffness decreases. From an engineering point of view, the most important difference for a cable with stiffness might be that the direction of the principal stress changes dramatically with a change in position within the neighborhood of a concentrated loading. This fact could be of considerable importance since the strength characteristics of cables are extremely direction dependent. Also, there are surfaces in the cable across which a compressive force must be transmitted for small amounts of bending stiffness. The paper discusses these facts in detail. Order of magnitude estimates of the most important effects are presented.