Tunneling Crack Initiation in Trailing-Edge Bond Lines of Wind-Turbine Blades

Tunneling cracks are observed in the adhesive of the trailing-edge bond line of wind-turbine rotor blades subjected to high-cycle fatigue. To identify the root causes of these cracks, their initiation was calculated using a stress-based approach. The mechanical stresses caused by aerodynamic and gravity loads, which arise when operating in the field, were considered on the one hand, and the residual stresses caused by thermal material shrinkage...