Relative movements within wire ropes bent over sheaves

The relative movements between the centre-lines of the strands of a wire rope during bending are analysed, as are the movements between the individual wires forming those strands. The formulae are applied to an example, and used to identify the position of greatest relative movement (slip). This position coincides with the most common location of wire failures in bend-over-sheave fatigue testing, suggesting that such slip calculations may form a valuable input to wire rope fatigue predictions.