Measurement of cyclic bending strains in steel wire rope

This paper reports strain gauge measurements of cyclic bending strain in th e wires of a six-strand right-handed Lang's lay steel wire rope running on and off a pulley. The paper describes the measurement procedures and presen ts the results for the two tests conducted which had different gauge config urations along and around the sample. It was found that the strain waveform s observed had some similarities with those reported elsewhere and the magn itudes of strains matched theoretical predictions. However, in contrast wit h behaviour reported for fluctuating tension, the initial differences betwe en and along wires rapidly attenuated. This observation helps to explain re ported similarities in bending fatigue performance of ropes from different sources which contrasts with the very significant differences in characteri stics found in tensile fatigue. The dependence of wire strain amplitude on rope bending deformation further contrasts with tensile fatigue in which wi re strain range is dependent on the local sharing of axial load.