TREE MACHINES FOR THE BENDING-TENSION FATIGUE OF ROPES
Wire rope is a flexible load transmitting medium with high strength to weight ratio, it is easy to handle, it has a good corrosion resistance when comprised of galvanized wires, it possesses a multi-load path with permits load sharing and is therefore used in a wide variety of applications. One of these applications is in the mooring of floating production and exploration platforms in the sea. In these situations the rope is usually stored on a winch drum from which the load is transmitted to the anchoring devices through a guidance system which is usually a series of sheaves. Although each anchor rope is appropriately tensioned to hold the platform on station, the motion of the platform due to the influences of~ currents, waves, wind and tide, is such that the rope experiences a fluctuating load, and a small (less than one lay length) oscillating rolling movements on and off the various sheaves and winch drums. The magnitude of these fluctuating loads and movements, which are related to some extent, is dependent on the severity of the prevailing conditions.
Author: David Waters, Ernst Ulrich