Empirical Factors in the Prediction of Helically Armored Cable Axial Stiffness

The object of this paper is to discuss the use of empirical factors in the prediction of armored cable axial stiffness. The stiffness of the armor wires and core that compose an armored cable are obtained from empirical data. To predict the net axial stiffness of a cable from the stiffnesses of its components a model of how the pitch diameter of an armor wire decreases as the cable is tensioned is required. The pitch diameter contraction is modeled in this paper by an experimentally determined Poisson’s ratio for the cable. The accuracy of cable axial stiffness predictions using these empirical factors is illustrated by comparing the results of mathematical models of armored cable to tension-elongation test data for ten different cables.