Multi-Scale Level Prediction of Crack Growth in Wind Turbine Blade Shear-Web Joints Applying Cohesive Zone Modelling

This manuscript presents the overview of the multi-scale level approach applied to the evaluation of disbond damage observed in the transition region of a large wind turbine blade. In particular in the bonded joint between the 3rd shear-web and the trailing edge sandwich panel. This work applies the Building Block Approach, adopted from the aircraft industry in the wind energy industry . It consists of performing a set of physical tests and virtual FEA simulations of increasing complexity to properly understand the fracture mechanism and its implications for the joint’s integrity. Results from the experimental test campaign suggest that quasi-static and fatigue crack propagation are dominated by large fibre bridging. As a result, non-linear numerical models based on Cohesive Zone Modelling are been proposed at three different scale levels to analyze quasi-static and fatigue crack propagation in the adhesive interface. Correlation between experimental and numerical results seems promising although further improvements in the formulation and calibration of the fatigue model are still a matter of development.