Page 67 - Failure Analysis Case Studies II

Fig. 4. Destranding of a six strand mooring rope.

Fig. 5. Hockles formed in the individual strands of an eight strand work wire.

‘birdcage’ damage through imposed twisting. But twisting, even without instabilities, is damaging
to these ropes because of the effect of unbalancing the load distribution between wires or strands
in different layers. This can reduce fatigue endurance significantly. By contrast, the wires in six
strand ropes retain a better load balance under twisting, so their fatigue performance is
maintained.