Integrity evaluation of offshore wind turbine MP-TP connection technologies

Student thesis: Doctoral Thesis

Abstract

To reach net-zero emissions in the UK by 2050, in accordance with Paris agreement (2016), the imperative role of renewable energy production has become evident globally. With the exponential growth in the installed capacity of offshore wind energy in the UK and around the world, the industry is continuously increasing the capacity of wind turbines, subsequently requiring larger structures to support them. Offshore wind turbines often consist of a foundation, a transition piece, and a tower. One critical component of the offshore wind turbine structures is the connection between the Monopile (MP) foundation, which is largely employed in the majority of offshore wind turbines currently installed around the world, and the Transition Piece (TP). This thesis investigates the suitability of both current and alternative MP-TP connection technologies to provide an in-depth knowledge of the advantages and disadvantages of each technology for potential use in future offshore wind farms. In this research study Finite Element Analysis (FEA) and analytical calculations are employed to investigate three distinct MP-TP connection technologies: threaded connection, C1 wedge connection and Slip Joint technologies. Further investigations have been carried out by reanalysing the existing fatigue data on various size and threaded connections available in the literature. Furthermore, through conducting new fatigue tests, this thesis contributes a comprehensive evaluation of the accuracy of the fatigue design curves recommended in international standards for large-scale bolted connections. The findings from this study underscore the potential of the existing flanged bolted connection technology as well as two novel technologies — namely C1 connection and Slip Joint — to address current and future challenges associated with the increasing size of offshore wind turbine structures. Moreover, they highlight the need for various feasible alternative solutions for MP-TP connections to be considered and employed in future offshore wind farms. This thesis provides a comprehensive analysis of the advantages and disadvantages of the mentioned MP-TP technologies. It identifies areas for further research to address the existing gaps in knowledge and enhance understanding of these innovative technologies for deployment in future offshore wind farm projects.
Date of Award3 Jun 2024
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)
SupervisorAli Mehmanparast (Supervisor) & Feargal Brennan (Supervisor)

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