Fretting wear and fatigue of crossed copper conductors under a variable coefficient of friction

Journal article, 2026

Dynamic submarine cables are subjected to long-term cyclic loading induced by waves, currents, and motions of floating offshore platforms. Fretting wear and fretting fatigue at the contact between conductor wires are rec-ognised as the primary mechanisms responsible for premature dynamic cable failure. Fretting fatigue life pre-diction depends on multiple parameters, among which the coefficient of friction (CoF) is particularly influential. Experiments show that the CoF evolves with the wear process, so assuming a constant CoF may lead to an inaccurate lifetime assessment. In this study, a three-dimensional finite element model of conductor fretting wear in a crossed-cylinder configuration with a variable coefficient of friction (VCoF) is developed. The numerical results are verified against the analytical solutions and experimental data, demonstrating excellent agreement. Cumulative fatigue damage is evaluated by a critical plane method combined with a material point mapping technique. The evolution of wear scar, contact pressure distribution, and cumulative fatigue damage of the conductors under fretting is systematically investigated. Furthermore, the effects of crossing angle, normal load, and slip amplitude on the fretting wear and fatigue life are analysed. Key findings reveal that fretting wear exerts a significant effect on fatigue life prediction, and accounting for the variation in the CoF alters the evolution of fatigue damage during the running-in stage. This study not only enhances the understanding of fretting fatigue behaviour in submarine cable conductor but also provides an effective predictive tool for assessing its mechanical service life.