Parametric FEA modelling of offshore wind turbine support structures: Towards scaling-up and CAPEX reduction

Parametric Finite Element Analysis (FEA) modelling is a powerful design tool often used for offshore wind. It is so effective because key design parameters (KDPs) can be modified directly within the python code, to assess their effect on the structure's integrity, saving time and resources. A parametric FEA model of offshore wind turbine (OWT) support structures (consisting of monopile (MP), soil-structure interaction, transition piece (TP), grouted connection (GC) and tower) has been developed and validated. Furthermore, the different KDPs that impact on the design and scaling-up of OWT support structures were identified. The aim of the analyses is determining how different geometry variations will affect the structural integrity of the unit and if these could contribute to the turbine's scale-up by either modifying the structure's modal properties, improving its structural integrity, or reducing capital expenditure (CAPEX). To do so, three design cases, assessing different KDPs, have been developed and presented. Case A investigated how the TP's and GC's length influences the structural integrity. Case B evaluated the effect of size and number of stoppers in the TP, keeping a constant volume of steel; and Case C assessed the structure's response to scour development. It is expected that this paper will provide useful information in the conceptual design and scale-up of OWT support structures, helping in the understanding of how KDPs can affect not only the structure's health, but also its CAPEX.