Centrifuge modelling of anchor performance for floating offshore wind turbines: installation and load behaviour in sand

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Drag embedment anchors (DEAs) are essential for the station-keeping of floating offshore structures, including wind turbines, energy converters, and LNG terminals. While traditional failure analysis often emphasizes potential material failures within anchor chains, the load displacement behaviour of DEAs is often overlooked. This contribution presents an experimental setup to model the installation process and the in-service loading of DEAs. Using a steel-printed DEA model, centrifuge tests were performed at an acceleration of 100g. Testing involved placing the DEA on a platform above the mudline, embedding it by pulling on the mooring line during spinning, applying sinusoidal loading to simulate different storm conditions, and pulling it out. The anchor's position over its drag distance was measured using a dyed soil layer and 3D scanning. The pull loads were recorded to assess the anchor's performance in sand. The results demonstrate that the combination of dyed soil layers and 3D scanning is an effective method for estimating the anchor trajectory. The load-displacement behaviour was minimally affected by the loading sequence, with an (RMSE) of 2.45 mm for penetration over displacement and 0.068 kN for anchor force over displacement between the tests with the different loading scenarios. Force profiles were consistent across tests. This study provides physical test data to validate numerical simulations and indicates that load-displacement response could be largely independent of loading order. The findings suggest Miners rule may apply to high-cycle loading, with future work focusing on high-cyclic loading analysis to refine predictive models and improve understanding of whole-life DEA performance.

5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG2025)

12 - Gravity base foundations, Drag and Plate Anchors