Co-authors​ :

 Dominik VOIGT , Fabian WUNDERLE (GERMANY), Mark OPITZ  

With the growing importance of renewable energy resources, the continuous development of wind turbines is crucial. A key factor in energy generation is the size of the rotor blades, as larger surfaces lead to enhanced wind energy absorption. The trend towards larger rotor blades increases the challenges in terms of transportation and assembly at operational sites. A viable solution involves segmenting the rotor blade into manageable sections, facilitating easier transportation and assembly, even at remote locations. During the operational period of the rotor blade, damaged segments can be replaced due to excessive wind loads or other environmental influences, such as erosion on the leading edge. In addition, this solution offers the possibility to efficiently dismantle the wind blades at the end of their service life and separate them into individual parts. Entire End of Life (EoL) segments or cut-out sections can be reintegrated into the product life cycle of a new wind turbine rotor blade, showcasing significant recycling potential. Furthermore, the use of adhesives is expected to offer a weight advantage over mechanical joining technologies.

Within the RECREATE research project, an approach is being pursued by INVENT in which design guidelines for adhesively bonded joints in segmented wind blade structures are developed. The geometric design guidelines are defined based on the positions of the adhesives, the occurring loads, and the involved joining parts, which are intended to be applied within a next generation rotor blade demonstrator in the research project. For this, a numerical model using the CZM (Cohesive Zone Model) method is created and various design options of adhesive joints in segmented rotor blades are compared. The model's material characteristics are represented by a thermal debonding-on-command adhesive. This adhesive contains particles that expand under heat, leading to cohesive failure within the adhesive layer and allowing damage-free disassembly of the blade segments. The performance and manufacturability of this model is evaluated using representative test specimens of selected joint geometries. Furthermore, the design of adherends in the rotor blade will be validated and optimized regarding various parameters. For example, factors like the reduction of adhesive consumption, the reproducibility and a stable process control with iterative bonding cycles are targeted. This research emphasizes the potential for innovative rotor blade designs to contribute significantly to the progression of sustainable wind energy technology.