Fluid-structure interaction analysis of lightweight large wind turbine blades based on internal rib configuration

Modern wind turbines are in the trend of super-large-scale development. However, super-large wind turbines will cause a rapid increase in blade weight, and then face a series of challenges in wind turbine systems, such as increased costs for installation and maintenance of offshore wind turbines, and increased deformation of blades. Therefore, it is necessary to carry out lightweight design for wind turbine blade structure. This study focuses on NREL 5 MW and IEA 15 MW wind turbine blades, proposing two types of inner rib structures—parallel inner ribs and bionic inner ribs—inspired by plant veins and aircraft wings. The structural performance of the blades under different yaw angles in extreme wind conditions was analyzed using CFD and FEM coupling method.Results indicated that compared with conventional blades, the weight of 5 MW inner ribbed blades can be reduced by up to 7.7%, and that of 15 MW inner ribbed blades by up to 2.9%. All blade designs meet the structural requirements for stiffness, strength, and stability. The flapwise deformation of the bionic rib blade decreased relative to conventional blades, but the maximum edgewise formation increased for eight inner ribbed blade configurations. The local buckling position of the inner ribbed blade shifted backward. Although the buckling factor of the bionic rib blade is reduced, it still satisfies stability requirements.