ABSTRACT
Monopile-supported offshore wind turbines (OWTs) are an efficient option to harness renewable energy. However, these structures need to withstand severe wind and wave loading conditions during their design life span. The damage vulnerability assessment of OWTs under such extreme scenarios can help stakeholders to prepare adequately and hence to minimize the losses. The present investigation attempts to assess the wave alone and combined wind and wave loading cases vulnerability assessment of benchmark NREL 5MW OWT for a practical water depth. Semi-empirical Morison equation and Det Norske Veritas (DNV) recommendations are used to get the wave and wind loads respectively on the structure. The overturning bending moment (OBM) at the monopile mud level is taken as the critical response, and the bending capacity is taken as the damage threshold. The OWT structural response is assessed for the considered water depth, and the fragility curves are generated for both the accounted load cases. The vulnerability of the OWTs under the considered load cases for the practical water depth are evaluated and compared.
