Impact of resin uptake of core materials on buckling of wind turbine blades

Wind turbine blades consist of thin-walled cylindric and airfoil-shaped structures, which are prone to buckling. In such lightweight structures, sandwich constructions are used to reduce weight and prevent stability issues. The leading and trailing edge panels of the blade in particular are designed as a sandwich, which requires an evaluation of the buckling, where shear crimping can be one of the critical failure modes. Shear crimping is critical when the through-the-thickness shear stiffness of the core is relatively low compared to the bending stiffness of the face sheets. In this study, shell and solid finite element (FE) blade models were benchmarked against each other in order to simulate the shear crimping failure mode. Additionally, analytic plate models were compared to FE for different sandwich thicknesses and core properties to identify shear crimping. For relatively thin sandwich constructions, the analytic plate models were closer to FE shell results, where as the models diverged when the sandwich was relatively thick. The importance of a realistic representation of core materials which takes into account the resin uptake in sandwich constructions of wind turbine blades was highlighted.