Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Numerical simulation of an installation process of a wind turbine assembly considering a pre-installed
monopile foundation
Zhongming Xiao 1, Kai Wang1,2*, Tianhui Liu1, Zhiyu Jiang3
1. School of Ocean Engineering and Technology, Sun Yat-Sen University, Zhuhai, China; 2. Southern Marine Science and Engineering
Guangdong Laboratory (Zhuhai), Zhuhai, China; 3. Department of Engineering Sciences, University of Agder, Grimstad, Norway

farms have constructed worldwide (Sadorsky, 2021).
Floating foundations and bottom-fixed foundations are two main
substructures for supporting offshore wind turbines. Floating
foundations include semi-submersible, Spar and tension leg foundations,while bottom-fixed foundations include monopile, gravity-based
foundation and jacket foundation(Wu et al., 2019). Compared withfloating offshore wind turbines, bottom-fixed offshore wind turbines are
more mature in technology and used more widely. Among the bottomfixed offshore wind turbines, monopile foundation is more often applied
than the gravity foundation and jacket foundation. Not only is thestructure of monopile foundation simpler and the production technology
is more mature, but also the cost of monopile foundation is lower.
Research of offshore wind technologies has been gaining
momentum since 2000. With the development and maturity of the stateof-the-art numerical simulation tools (Jiang et al., 2018b), coupled
dynamic analysis of offshore wind turbines (OWTs) becomes possible.
However, most of the related literature is focused on design and analysisof OWTs in various operational or parked conditions. In contrast, there
are limited research work on installation of OWTs. Gao et al. (Gao et al.,2018) did a summary of the recent work at NTNU on marine operations
related to installation of offshore wind turbine, proposing some novel
installations concept like pre-assembled rotor-nacelle-tower and single
blade installation concept. Verma et al. (Verma et al., 2019) establisheda multi-body numerical model of a single-blade model with tugger lines
and a monopole model, considering a realistic scenario of the matingprocess and investigating the consequences of such impact loads. Jiang
et al. (Jiang, 2021) drew a conclusion about offshore wind turbine
installation review, introducing the installation methods and proceduresof bottom-fixed and floating offshore wind turbines. Zhao et al. (Zhao etal., 2018) developed a numerical model to study dynamic motion
response of an offshore wind turbine blade during installation by a jackup crane vessel and investigated the influence of the wind and wave

ABSTRACTThe installation phase is a critical stage during the lifecycle of anoffshore wind turbine. The technology development of bottom-fixedoffshore wind turbines is more mature compared to that floating windturbines. This paper focuses on the installation process of an offshore
monopile wind turbine using a previously proposed catamaran
installation vessel. The simulated installation process involves thecatamaran installation vessel, a lifted 5-MW wind turbine assembly anda pre-installed monopile foundation. Time-domain numericalsimulations are conducted for the coupled catamaran-monopile systemwith mechanical coupling. The forces on the monopile foundation andthe motion responses of the catamaran during the process are analyzed.
Finally, this study calculates the catamaran response motion and theforces on sliding grippers of the coupled installation model, exploring
the influence of sea state parameters on the coupled installation modeland comparing the forces on sliding grippers of two different coupledinstallation models.

KEY WORDS: wind turbine; monopole foundation; catamaran;
installation coupled model

INTRODUCTION
In recent years, offshore renewable energy resources have attracted
extensive attention all over the world, due to the substantial increasedemand of traditional energy and the shortage of energy resources suchas oil and coal. Offshore wind energy is one the most mature form ofmarine renewable energies. At the end of 2020, the global cumulative
installed offshore wind capacity reached 32.5GW, with an increase of
19.1% from the end of 2018 (Council, G. W. E. 2021). In 2020, the global
installed offshore wind capacity reached 5206MW, 15 offshore wind373