Simplified estimation of helically steel armored cable elongation, diameter reduction, and rotation

The tension-induced elongation, diameter reduction, and rotation characteristics of helically steel armored cables are governed by complex non-linear relationships that are a function of cable design, materials, and manufacture. Estimation of cable performance using non-linear analysis techniques can be time-consuming and difficult, requiring a level of effort that often is not appropriate for preliminary engineering estimates. Making the simplifying assumption of a non-compressible cable allows the use of linear wire rope equations; however, this approach often leads to poor and misleading estimates. Recognizing the need to obtain quick, accurate, and easy-to-calculate estimates of cable response under tension, Vector Cable performed an analysis of its large database of cable test results. By obtaining a proportional fit to the basic physical relationships governing linear elastic behavior of materials, Hooke´s law and the elastic torsion formula, Vector Cable has developed techniques for simplified estimation of helically armored cable elongation, diameter reduction, and rotation