A NOVEL FATIGUE STRESS MODEL OF POWER PHASES AND COATED TUBES IN DEEP-WATER POWER CABLES, UMBILICALS, AND POWER UMBILICALS

摘要

Short fatigue life is a significant challenge for power cables, umbilicals, and power umbilicals to be installed in ultra-deep and hyper-deep waters. This paper presents a novel model for calculating fatigue stresses in conductors of power phases and in tubes with coating. The novelty is that the axial displacement of the conductor within the electric insulation system, or the tube within the sheath, is taken into consideration. For a real-life power cable designed for 2 300 m water depth, the novel model gives a reduction in fatigue stress of 69% compared to the traditional resultant-based approach for oscillations smaller than the slip curvature. This corresponds to a reduction in fatigue damage of more than 99%.