Fatigue strength of fixed offshore structures under variable amplitude loading due to wind, wave, and ice action

Article Number
V006T07A020
Citation
ASME 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2022)
Contribution to Conference
ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2022  
Publisher DOI
10.1115/OMAE2022-78068
Scopus ID
2-s2.0-85140913006
Fixed offshore wind turbines are increasingly developed for high latitude areas where not only wind and wave loads need to be considered, but also moving sea ice. Current structural design rules do not adequately consider the effect of ice loading on fatigue life, due to missing studies on fatigue strength of welded joints under combined wind, wave, and ice action. Thus, a methodology to determine combined variable-Amplitude loading (VAL) spectra was developed in a previous study. The stress state time-history at an exemplarily selected point in the support structure of an offshore wind energy monopile was translated into a VAL sequence. This sequence is used as an input for fatigue tests of butt-welded joints in the current study. The current study presents the VAL spectrum and the corresponding VAL time series, the results of the fatigue tests and compares them to typical fatigue damage sums for other stress spectra.
Subjects
Arctic technology
Ice loads
Offshore renewable energies
Stress analysis
Structural integrity
Wind turbine fatigue damage and life extension