Mechanical behaviour of the metallic elements of submarine cables as a function of cable loading

Abstract

Submarine power cables are widely used for local and national distribution and it is of interest to know their mechanical limitations particularly with regard to the loads experienced during the installation process where static or low-cycle fatigue failures are possible. A detailed understanding of the global and internal mechanics of such cables is therefore of interest in order to achieve the required performance at reasonable weight. This paper addresses the relationship between applied loads and the responses of the metallic elements within typical subsea configurations. The existing theory on mechanics of cables of this type is extended to take into account strain distributions within helical elements and to model the interactions between loading modes as well as including nonlinear effects associated with plasticity in the metallic elements and compliance of the polymeric material within the composite construction. The results of a number of material tests are incorporated into the new analysis and the predictions of the model are also compared with measurements on the conductors of cables under conditions of axial and bending loading.