Quantitative wear estimation for floating structures by using 3-D geometry of mooring chain

Takaaki Takeuchi, Tomoaki Utsunomiya, Koji Gotoh, Iku Sato

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

For reducing the maintenance cost of floating offshore wind turbine structures, it is necessary to establish a quantitative wear estimation method for the mooring chains. In this paper, attempts have been made to improve the accuracy of the estimation method in terms of the mooring chain model. These investigations were performed about a spar-type floater moored with three catenary mooring lines at Goto, Nagasaki prefecture, Japan. Up to now, the mass-spring model had been used for the mooring chain in response analysis and the relative angle between two spring lines was considered as only a sliding angle without friction. However, there is also rolling in the motion between mooring links, which should cause less wear than by sliding. In this study, the detailed motion of the link in response analysis is calculated and applied to the wear estimation by using a 3-D model in MSC. Adams. This enables the wear estimation considering link motion closer to a real phenomenon. A Contact analysis between the 3-D chain model requires some contact properties (e.g. contact stiffness and friction). In this paper, these properties are calculated based on the Hertzian contact method and FEM analysis. As a result, the wear amounts overestimated by using the mass-spring model in the previous investigation, especially at the point located clump weight and touchdown point, decrease getting closer to the measurements. In addition, by tracking the contact points it is found that the major motion caused between links is the rolling. For future works, there remains a need for further validation and the consideration of elasticity between mooring links, impressions caused by proof load test and the effect of corrosion.

Original languageEnglish
Title of host publicationOcean Space Utilization
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791884362
Publication statusPublished - 2020
EventASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2020 - Virtual, Online
Duration: Aug 3 2020Aug 7 2020

Publication series

NameProceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
Volume5

Conference

ConferenceASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2020
CityVirtual, Online
Period8/3/208/7/20

All Science Journal Classification (ASJC) codes

  • Ocean Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering

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