A practical approach for the peel stress prediction in the trailing-edge adhesive joint of wind turbine blades

Wind turbine blades consist of thin-walled cylindric and airfoil-shaped structures, which are prone to "breathing" or "pumping" when subjected to cyclic loading. The "pumping" induces a peel stress in the adhesive layer of the trailing-edge bond line. To take account of this peel stress in the design phase, adequate models are required. State-of-the-art blade finite element (FE) models are usually implemented using shell elements. The trailing-edge joint is often represented by solid elements that are connected with the shell elements. The peel stress peak of interest occurs at the edge of the adhesive joint, which is, subject to a singularity, however. This study proposes a practical approach to estimate the peel stress peak in the adhesive joint with the help of the analytical solution which approximates and extrapolates the FE results. Moreover, different modeling techniques are benchmarked in respect of the peel stress prediction.