Structural integrity analysis of marine dynamic cables: water trees and fatigue
Journal article, 2025
Offshore power cables are typically designed to have a service life of around 25 years. A pattern is emerging where these cables only last 10 years or even as little as two. The main consensus as to why the service life is so short is due to a combination of fatigue and fretting/wear damages of the copper conductors and water treeing in the insulation material. This study presents a method that can be used to analyze the structural integrity of dynamic subsea power cables and estimate their service life determined by the factors above. The numerical simulation models developed and used to carry out global and local fatigue analyses of dynamic subsea power cables are presented, together with methods and models for assessing fretting, wear, and growth of water tree defects. A methodology for structural integrity assessment that includes all these factors is proposed. A dynamic subsea power cable connected to a wave energy converter is used as the case study for comparison of the service life when these factors are considered compared to when, e.g., the growth of water trees is excluded. A numerical sensitivity analysis demonstrates that the value of the seawater’s electrical conductivity and the insulation material’s threshold stress-intensity factor greatly influence the cable’s service life.
structural mechanics and foundation
dynamic power cable
computational mechanics and design
risers
system integrity assessment
fretting
Maxwell stress
water tree
subsea technology
numerical simulation
wear
fatigue and fracture reliability and control
material performance and applications
dynamics of structures
moorings and cable dynamics
fatigue analysis
floating and moored production systems
Author
Jonas Ringsberg
Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology
Zhiyuan Li
Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology
Robbie McCormick
University of Strathclyde
Nicholas Fagan
University of Strathclyde
Greg Stewart
University of Strathclyde
Tom Marwood
University of Strathclyde
Journal of Offshore Mechanics and Arctic Engineering
0892-7219 (ISSN) 1528-896X (eISSN)
Vol. 147 June 031702-1-031702-3WATERTREE – Predicting failure of dynamic subsea cables by insulation breakdown
Swedish Energy Agency (50156-1), 2020-09-01 -- 2022-03-31.
Driving Forces
Sustainable development
Innovation and entrepreneurship
Subject Categories
Materials Engineering
Applied Mechanics
Vehicle Engineering
Electrical Engineering, Electronic Engineering, Information Engineering
Areas of Advance
Transport
Energy
Materials Science
Roots
Basic sciences
Infrastructure
C3SE (Chalmers Centre for Computational Science and Engineering)
DOI
10.1115/1.4065816