Comparison of rope fatigue life using two different test methods

Fatigue life is one of the most significant features related to wire rope utilization and many studies have been done throughout the years to understand this phenomenon and build up a reliable model. The most common test arrangement for fatigue evaluation is the “Bending Over Sheaves” one, while another method consists of rotating the rope into a U shape around its axis with no components in between, considering only the intrinsic fatigue of the rope. Although less popular, the latter method can provide results in a much faster, reliable and cheaper way. In order to establish the correlation between the results of the two tests and to find a “translation factor”, an extensive campaign has been performed. This consisted of testing several samples of 8 strand compacted rope taken from the same master reel using both methods. At the completion of the tests, the number of cycles at discard have been compared and the rope samples have been dismantled in order to verify the shape and the position of all the breaks.

Author(s): L.Lombardi