Wind turbine design relies heavily on accurate prediction of blade structural response under aerodynamic loading. Traditional aeroelastic tools combine Blade Element Momentum (BEM) theory for aerodynamic calculations with beam finite element models for structural analysis. While computationally efficient, this approach sacrifices detail in how loads transfer to blade structures.
Researchers have introduced an improved methodology that bridges aerodynamic simulation tools with higher-fidelity multibody models using the Floating Frame of Reference Formulation (FFRF). Rather than treating blades as simple beams, this method employs solid finite elements to capture more realistic structural behavior, then reduces computational complexity through the Hurty/Craig-Bampton method and interface reduction techniques.
The key innovation involves efficiently transferring distributed aerodynamic loads from BEM codes to the reduced-order model. By calculating equivalent concentrated loads and applying them via interpolation multipoint constraints (RBE3), the approach avoids computational bottlenecks. Two strategies were tested to prevent load application to internal model nodes: interface modes and minimum strain energy formulation.
Testing on a 12.6-meter wind turbine blade revealed important insights. Adding load interfaces at cross-sections improved torsional response prediction compared to standard beam models, addressing a known weakness in traditional approaches. However, the overall accuracy gain remained modest for most loading conditions. Notably, minimum strain energy interfaces inadvertently increased model stiffness, suggesting potential trade-offs in implementation choices.
This research advances wind turbine simulation methodology by enabling designers to use higher-fidelity structural models without prohibitive computational costs. The improved torsional prediction is particularly valuable for large modern turbines experiencing complex loading. Future work should explore the method's application to floating offshore turbines and integrate real-time validation against field measurements from operational blades.
