Development and applicability of a novel hybrid framework for aeroelastic and stress analysis of floating offshore wind turbine blades

This paper presents a multi-fidelity hybrid simulation framework for analyzing aeroelastic responses and structural stress of large-scale floating offshore wind turbine blades under combined wind-wave conditions. This framework integrates OpenFAST with 3D shell-based finite element analysis tool, ANSYS through a novel dynamic load mapping interface for preventing spurious stress concentrations caused by conventional methods. The time-varying equivalent sectional resultant loads acting on blade section nodes obtained by OpenFAST are properly converted to 3D equivalent distributed surface load on blade suction and pressure surfaces, and then applied on the elaborate structure model in ANSYS. Using the DeepCWind 5 MW floating offshore wind turbine as a case study, the differences in blade dynamic response, stress distribution, and structural risk indicators between the selected 0° and 15° yaw cases under extreme wind condition is investigated. The results show that the 15° yaw misalignment causes the maximum blade-shell von Mises stress increases by 92.4%, from 66 MPa to 127 MPa. Based on the Tsai-Wu criterion, the maximum strength ratio of the shear web increases to 0.72 under 15° yaw misalignment, remaining below the unity failure threshold but indicating a substantially reduced failure margin. The dominant high-risk region shifts from the trailing edge in the airfoil transition section to the spar cap–shear web joint near the blade-root, which is attributed to severe bending–torsional coupling induced by yaw misalignment. This indicates that yaw misalignment may shift the critical high-risk region from local trailing-edge stress concentration to the blade-root spar cap–shear web joint, indicating increased structural demand and a substantially reduced failure margin in the primary load-bearing region. This study offers critical insights into the structural dynamic behavior of FOWT's blades, which are expected to provide guidance on how to design resilience-enhanced blades against extreme parked wind-wave conditions.