Multi‐hazard fragility assessment of monopile offshore wind turbines under earthquake, wind and wave loads

This study establishes a multi-hazard probabilistic assessment framework for assessing the integrity of monopile offshore wind turbines (OWT) under stochastic coupled effect wind, wave and earthquake loading. The procedure deals with entire operational range inflow speed (i.e., 3–25 m/s), which probability failure excitations is found to be non-negligible. Numerical analysis performed by implementing nonlinear finite-element models OWT developed in OpenSees. dynamic response system wind- wave-load combinations individually validated against those obtained from aero-hydro-servo-elastic simulator OpenFAST. Following Latin-hypercube approach, cloud-based then an ensemble 300 ground motions, performance regarding serviceability limit state (SLS) ultimate (ULS) can evaluated. epistemic uncertainty associated various loads, structural properties, soil conditions also accounted for. Based on this framework, sensitivity resulting fragility surfaces different statistical regression methods wind—ground motion intensity measure pairs (IM-pairs) further scrutinised. Regression are comparatively efficiency, practicality, proficiency sufficiency IM-pairs examined purpose operating functions. optimum IM-pair employed trained Gaussian Process (GPR) scheme cloud data assess system. derived function shows that contribution seismic forces demand design-level comparable caused operational-level loads.