Structural Optimization of Wind Turbine Blades Including Fatigue Constraints

Designing modern wind turbine blades is challenging due to the large scale and advanced materials utilized. Structural optimization has been shown to provide substantial benefits to both the design process and resulting design, however its application to blades is non-trivial, because of the required computational cost of solving optimization problems. Moreover, it is desirable to assess all structural failure criteria as part of the optimization, which is currently not possible, herein notably fatigue damage.
The present work hence aims to further the structural optimization capabilities in application to wind turbine blades. Initial work concerns development of a fatigue optimization approach for general laminated composite structures within a gradient-based framework. The developed approach is later applied to optimize a blade root section model, along with buckling and static failure criteria, in context of both a thickness and multi-material and thickness parametrization. Significant reductions in material from the initial design accompany the attained variable-thickness laminates, emphasizing the potential of using the developed methods in the design process.