Seismic responses of different types of offshore wind turbine support structures

• Published in: Ocean engineering 2024-04, Vol.297, p.117108, Article 117108
• Main Authors: Ngo, Duc-Vu, Kim, Dong-Hyawn
• Format: Article
• Language: English
• Subjects: Dynamic response; Earthquake; Fragility curve; Offshore wind turbine (OWT); Wind load
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2024.117108

This study employed numerical analysis to compare the seismic performance of different types of offshore wind turbine foundations: pentapod suction bucket, monopile, and pile jacket foundation. The finite element model of these foundations was modeled by Abaqus and was then verified by modal analysis. GH-Blade was used to create the wind field and eventually generated the thrust force by the wind which was then fed into the Abaqus. First, three earthquake records, i.e. El-Centro, Taft, and Topanga, were used to investigate the dynamic response of these OWTs. Then, a set of 16 earthquake records was used in fragility analysis. Under the combination of these earthquake loads and wind, the dynamic responses were obtained and then converted to the fragility curves to evaluate the probability of exceeding different damage states. The results show that OWT supported by monopile foundation (MP-OWT) has the largest top displacement. Despite occurring almost in the same position, the maximum stress on the tower of OWT supported by pile jacket foundation (J-OWT) is larger about 17.7% and 21.3% than that of OWT supported by suction bucket foundation (SB-OWT) and MP-OWT, respectively. The analysis also indicated that MP-OWT has a high risk in terms of tower-top displacement compared to the others while J-OWT was the most sensitive in terms of tower-base moment and tower stress. The paper provided an overview of the seismic response of different OWT foundations, thereby helping in seismic design for wind turbines. •Three-dimensional finite element analysis was conducted to predict the dynamic response of OWTs.•Seismic responses of OWTs supported by different foundation types were compared.•The probability of exceeding several damaged states within the OWT system was investigated.