Fracture mechanics approach for failure of adhesive joints in wind turbine blades

• Cohesive zone model approach can be used to predict blade joint failure.
• Shear stress is mainly responsible for blade skin–web joint failure.
• Blade joint debonding initiated prior to reaching the extreme design loading.
• Debonding propagated progressively with load increase.

Composite components of wind turbine blade are assembled with adhesive. In order to assess structural integrity of blades it is needed to investigate fracture of joints. In this study, finite element analysis based on fracture mechanics was conducted to characterize failure of adhesive joint for wind turbine blade. The cohesive zone model as proposed fracture mechanics approach was verified through the comparison of numerical results with experimental data. Finite element models of wind turbine were developed to predict damage initiation and propagation. Numerical results based on fracture mechanics showed that failure was initiated in the edge of the adhesive bond line due to high level of shear stress prior to reaching the extreme design loading and propagated progressively.