J W S Hearle, R E Hobbs, M S Overington and S J Banfield
The modelling of long-term fatigue performance of twisted ropes has been extended to cover axial compression fatigue. This mode of failure has been observed in use and testing of ropes. It is characterised by sharp cooperative kinking of yarns, which leads to flex fatigue breakage of fibres. A model of pipeline buckling was modified to allow for plasticity in bending. The axial and laterla restraints, which influence the buckling, were derived from the existing rope mechanics model. Axial compression was introduced into the total computational model, in order to predict the form of buckling and the consequent fibre failure. An alternative use of the program is simply to detect conditions in which axial compression occurs as an indication of the occurrence of fatigue.
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