A model for quick load analysis for monopile-type offshore wind turbine substructures

Abstract. A model for quick load analysis, QuLA, of an offshore wind turbine substructure is presented. The aerodynamic rotor loads and damping are pre-computed for a land-based configuration. The dynamic structural response is represented by the first global fore-aft mode only and is computed in the frequency domain with phases using the equation of motion. The model is compared to the state-of-the-art aeroelastic code Flex5. Both lifetime fatigue and extreme loads are considered in the comparison. In general there is good agreement between the two models. Some deviations for the sectional forces are explained in terms of the model simplifications. The differences in the sectional moments are found to be within 10 % for the fatigue load case and 10 % for the extreme load condition.