Simulation Study on Methods for Reducing Dynamic Cable Curvature in Floating Wind Power Platforms

• Published in: Journal of marine science and engineering Vol. 12; no. 2; p. 334
• Main Authors: Guo, Zhitao, Zhao, Xudong, Ma, Qingfen, Li, Jingru, Wu, Zhongye
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2024
• Subjects: Air-turbines; Alternative energy sources; Bending stresses; cable curvature; Cables; Carbon; Connecting; Cumulative damage; Curvature; Deformation; Design; dynamic cable; Emission standards; Fatigue; fatigue analysis; Fatigue failure; Fatigue life; Fatigue testing machines; Floating; floating wind power platform; Green technology; hanging angle; Hydrostatic pressure; Life prediction; Load; Marine environment; Materials; Materials fatigue; Methods; Ocean currents; Offshore; S N diagrams; Safety factors; Service life; Simulation methods; Software; Stiffeners; Turbines; Water depth; Wind power; Wind turbines; China
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse12020334

As a key component connecting a floating wind turbine with static sea cables, dynamic cables undergo significant tensile and bending loads caused by hydrostatic pressure, self-weight, waves, and ocean currents during service, which can lead to fatigue failure. Thus, dynamic and fatigue analyses are necessary for the design and operation of dynamic cables. In this study, a fatigue analysis of the three-core four-layer armored dynamic cable used in a semisubmersible floating wind turbine was carried out at a water depth of 25 m. The Miner linear cumulative damage method, based on material S-N curves, was used to predict fatigue life. The results indicate that, at 10 times the safety factor, the dynamic cables meet the design requirement of a 30-year service life in the studied marine environment. The maximal curvature of the dynamic cable always appears at the exit of the bend stiffener, even beyond the allowed point. Adding weights to the section where the cable exits the bend stiffener and adjusting the bend stiffener’s hanging angle can both reduce the curvature at the bend stiffener exit. The scheme of adjusting the bend stiffener’s hanging angle is preferred, for it is easier for simultaneous adjusting and inducing much smaller extra stress in the cable. As the hanging angle increases, the curvature at the bend stiffener exit decreases, while the maximal effective tension and maximal von Mises stress gradually increase. For certain operating conditions, especially with higher waves, it is better to adjust the hanging angle to avoid excessive curvature and, meanwhile, ensure the increase in the stress within a reasonable range.