Analysis of Large Diameter Steel Ropes

Abstract

The theoretical analysis of a large diameter wire rope, using results from a reported orthotropic sheet model for analyzing the behavior of its constituent helical strands, is reported in this paper. The present model is (unlike available theories on wire ropes) capable of catering to the effects of interwire friction. Experimental results (reported elsewhere) indicate that under axial cyclic loading superimposed on a mean tension, the rope-effective axial stiffness, with its ends fixed against rotation, is not a constant and, in the presence of friction, varies between upper (no-slip) and lower (full-slip) bounds. The present theory provides a fairly simple means to obtain the upper and lower bounds to rope-effective axial stiffness, with encouraging correlations found between the theoretical predictions and experimental data for some realistic wire ropes. Simple methods are also suggested for predicting the wire-rope stiffness coefficients under both the no-slip and full-slip conditions which cater to the effect of axial/torsional coupling.