Understanding fatigue damage initiation and propagation of composite wind turbine blades is an essential step towards the design of reliable prognostic health management systems (PHM) and to improve lifetime predictions. This study presents a numerical and experimental investigation of the debonding process in the spar cap/shear web region of a full-scale composite wind turbine blade under fatigue loading.
For this purpose, numerical simulations have been performed to design and specify the size and locations of artificial defects to provoke steady, controllable damage growth in the adhesive bondline between the rear shear web and cap region of the DTU 12.6m wind turbine blade under fatigue loading. Subsequently, these artificial defects are embedded into the manufacturing process of the composite wind turbine blade with the help of slip foils and partially perforated slip foils to create regions with no bonding, 30% and 50% bonding of the contact surfaces of the adhesive joint, respectively.
The numerical predictions and experimental results of the damage growth in the adhesive joint are compared. The observations demonstrate the complexity of damage growth of composite structures under fatigue loading and the necessity of accurate numerical prediction tools for reliable prognostic health management systems.