Fragility analysis of an ageing monopile offshore wind turbine subjected to simultaneous wind and seismic load

Abstract

The loads induced as a result of seismic activities may jeopardize the serviceability of offshore wind turbines or may even lead the structure to reach the ultimate strength. The maximum load-carrying capacity of a support structure can be estimated by performing a structural assessment which accounts for the nonlinear effects arising from the material and geometry. The present work aims to analyze the fragility of a 5 MW monopile offshore wind turbine structure subjected to seismic activities accounting for soil interactions and time-variant structural degradation. The offshore wind turbine structure is subjected to different ground motions with different intensity. The nonlinear full transient dynamic structural analysis is carried out based on the finite element method, and the nonlinear monopile structural response during the different seismic activities is discussed. Finally, the fragility curves associated with the serviceability limit state design and the ultimate strength limit state are developed.

Damage Monitoring of a Catenary Moored Spar Platform for Renewable Energy Devices

“…Experimental studies of damage responses and the variability of such responses of offshore renewable energy platforms can lead to guidelines and recommendations for scaled testing, and lifetime risks can be better understood at lower technological readiness levels. It would also address some of the epistemic uncertainty that exists around the responses to damages over operational lifetime [24][25][26][27]. Such experiments would also eventually be used to calibrate numerical simulations against extreme value responses [28].…”