Inspection and Maintenance Planning for Offshore Wind Support Structures: Modelling Reliability and Inspection Costs at the System Level

peer reviewedIn the context of achieving a decarbonized economy, wind farms installed farther offshore provide the opportunity of harnessing more stable wind energy. Exposed to the combined cyclic loading of wind and waves, offshore wind substructures withstand, however, harsh fatigue and corrosion deterioration mechanisms throughout their operational life. In this scenario, Inspection and Maintenance (I&M) planning methods enable efficient control of structural failure risks by timely allocating inspection and maintenance interventions. In this work, we discuss the benefits of approaching I&M planning at the system level, thus determining strategies that are influenced by system risk metrics. To support the discussion, I&M policies are identified for an offshore wind support structure composed of 12 fatigue hotspots located at three weld connections and exposed to varying corrosion-fatigue deterioration intensities. Within the numerical experiments, the heuristics-based policy search is conducted both at component and system levels, exploring various structural redundancy settings. The results demonstrate that a systematic treatment of structural reliability can only be achieved by modelling the entire structural system, assigning and considering global failure risk metrics during the policy search. Independently of the investigated structural reliability model, system-based I&M policies outperform component-based strategies.MAXWind – MAintenance, Inspection and EXploitation Optimization of Offshore Wind Farms subjected to Corrosion-Fatigu