Modeling the progressive failure of scarf joints for wind turbine blade repair

Abstract

A continuum damage model for simulating propagation of debonding in joints, introducing a linear softening damage process for the adhesive agent, is used to predict failure of scarf joints. The proposed modeling procedure was applied to scarf joints of marine type with glass fiber reinforced polymer adherends, commonly encountered in wind turbine rotor blade repair. Tests on aviation type scarf joints with carbon fiber reinforced polymer adherends were also simulated. Stress analysis was performed using plane strain elements of a commercial finite element code allowing implementation of user-defined material behavior. Numerical results for different scarf angles were in good agreement with the experimental data. The proposed model has been utilized to design a repair patch on wind turbine rotor blade and the design has been validated by testing a full-scale subcomponent of the repaired blade.