OIPEEC – International Organization for the Study of Ropes

Torque cycle fatigue of wire ropes

Briem, U. Torque cycle fatigue of wire ropes, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0810 , 99-106, ISBN: 978-0-9552500-1-9.

Running ropes have a limited service life. Material fatigue is caused by oscillating bending stress as the rope runs over sheaves and by pulsating tension-tension stress during service. Oscillating bending stress and fluctuating tension-tension stress may occur simultaneously too. Depending on the application, one of these forms of loading is predominant. In applications with friction winders and high lifting heights such as occur in the mining industry, the rope opens and closes itself in a cyclic manner while running through the shaft. These torque stresses also lead to material fatigue. Beyond a certain shaft depth material fatigue is caused mainly by the torsional stress. In the paper, torque tests are reported and an equation for describing the expected service life introduced. (5 refs.)

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