Reliability-based design optimization of offshore wind turbine support structure considering pile-soil coupling effect

The significant portion of the overall capital costs of wind turbine projects attributed to the tower and support structure necessitates that the wind power industry implements optimization strategies that ensure reliability while minimizing costs. This paper presents a reliability design optimization method for offshore wind turbine support structures that incorporates the impact of pile-soil coupling. The method begins with parametric finite element modeling of monopile support structures and foundations for offshore wind turbines, considering both pile-soil coupling and the combined effects of wind and wave forces. Subsequently, the constraints in the optimization design for reliability are represented through a surrogate model that corre lates the full parameters of the finite element model with the structural response. These constraints encompass modal frequency, stress, strain, buckling, variable range, and the reliability index. Ultimately, a lightweight design is realized by harmoniz ing these multiple constraints, thus meeting the reliability standards prescribed by turbine design criteria.