Elsevier

Energy Procedia

Volume 80, 2015, Pages 193-200
Energy Procedia

Sensitivity of Wave Fatigue Loads on Offshore Wind Turbines under Varying Site Conditions

https://doi.org/10.1016/j.egypro.2015.11.422Get rights and content
Under a Creative Commons license
open access

Abstract

Considerable variations in environmental site conditions can exist within large offshore wind farms leading to divergent fatigue loads on support structures. An efficient frequency-domain method to calculate wave-induced fatigue loads on offshore wind turbine monopile foundations was developed. A verification study with time-domain simulations for a 4MW offshore wind turbine showed result accuracies of more than 90% for equivalent bending moments at mudline and interface level. This accuracy and computation times in the order of seconds make the frequency-domain method ideal for preliminary design and support structure optimization. The model is applied in sensitivity analysis of fatigue loads using Monte-Carlo simulations. Local and global sensitivity studies and a probabilistic assessment give insight into the importance of site parameters like water depth, soil stiffness, wave height, and wave period on fatigue loads. Results show a significant influence of water depth and wave period. This provides a basis for design optimization, load interpolation and uncertainty analysis in large wind farms.

Keywords

Offshore wind turbines
wave fatigue load
sensitivity analysis
frequency-domain
site variation

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Peer-review under responsibility of SINTEF Energi AS.