Mechanical study of Twintex-TPU adhesive joints for leading-edge erosion protection of wind turbine blades

Wind turbine blades are constantly subjected to harsh environmental conditions, particularly at their leading edges, which are highly vulnerable to erosion due to high-velocity impacts from rain droplets. This erosion reduces the aerodynamic efficiency and lifespan of wind turbine blades, leading to increased maintenance costs and potential structural failures. In this study, thermoplastic polyurethane, which is known for its excellent erosion resistance, was bonded to the leading edge of a conventional Twintex wind turbine blade using an adhesive joint, with the objective of enhancing erosion resistance while maintaining desirable mechanical performance. Three industrial adhesives including Permabond TA4610, Permabond TA4611 and Gorilla were used for in the standard adhesive joints. The shear and opening modes as prevalent failure modes in adhesive joints were investigated for material characterisation tests. The shear lap specimens with Permabond TA4611 showed highest shear strength, which was 10.6% greater than that of Permabond TA4610 whereas in the double cantilever beam specimens for opening mode tests the PermabondTA4610 provided the highest fracture energy with 175.6% higher than TA4611 and 241.4% higher than Gorilla adhesive, indicating superior resistance to peel forces. Based on the mechanical results and adhesive costs the Permabond TA4610 was selected to bond thermoplastic polyurethane onto the Twintex blade in the leading-edge. Structural testing and numerical modelling on the Twintex blade showed that the failure occurred outside the leading-edge protection system, confirming a proper adhesive was selected. Enhancing blade durability through advanced leading-edge erosion protection system supports cleaner power generation and reduced environmental impact.