Finite Element Modeling of Wind Turbine Blades

*† ‡ The typical approach to modeling a full wind turbine blade with the finite element method (FEM) has been to use layered shell elements with the nodes offset to the exterior surface. Though the bending response of the blade is of primary interest, the previous few years have seen increased interest in blades incorporating bend-twist coupling. In the analysis of such blades, the torsional response is critical. Unfortunately, recent FEM analyses (layered shell elements, offset nodes) have shown the results for a full-blade model with a torsional load to be erroneous. This paper describes the pitfalls associated with offset nodes for a layered shell element, the issues associated with modeling a wind turbine blade with mid-thickness shells, and a discussion of the feasibility of migrating from shell elements to either layered or non-layered solid (brick) elements.