Fatigue life prediction for cables in cyclic tension

Cables are used in civil and mining engineering applications, such as in cable stays for suspension bridges, elevators, construction cranes, mining shovels and draglines. Such cables are mainly used for supporting or hoisting and can be considered to be either stationary or running cables. In supporting functions, cables are subjected to cyclic tension, with the primary mode of failure due to fretting fatigue of individual wires that make up the cables as they abrade against each other. Stationary cables subjected to cyclic tension (tension-tension) fatigue are the focus of this work, and although other researchers have investigated the fatigue life of such cables, there remains much of the cyclic tensile behavior that needs further investigation. The stress condition of several cables such as 19-, 91- and 92-wire strands; independent wire rope core; and the 6 x 19 Seale-independent wire rope core wire ropes was investigated using finite element modeling techniques. A stress-based approach was used with the results of finite element modeling to obtain the fatigue life for these cables. In practice, it would be challenging for a finite element analysis to be carried out each time the fatigue life of a cable is needed, so in a preventive maintenance stance, regression coefficients have been proposed for use with a fatigue life prediction model.