Structural analysis of large-scale vertical axis wind turbines Part II: Fatigue and ultimate strength analyses

Vertical axis wind turbines (VAWTs) exhibit many advantages and great application prospect as compared with horizontal ones. However, large-scale VAWTs are rarely reported, and the codes and guidelines for designing large-scale VAWTs are lacking. Designing a large-scale composite blade requires precise finite element (FE) modeling and stress analysis at the lamina level, while precise modeling of an entire VAWT is computationally intensive. This study proposes a comprehensive fatigue and ultimate strength analysis framework for VAWTs. The framework includes load determination, finite element (FE) model establishment, and fatigue and ultimate strength analyses. Wind load determination has been presented in the companion paper. In this study, laminated shell elements are used to model blades, which are separately analyzed by ignoring the influence of the tower and arms. Meanwhile, beam elements are used to model an entire VAWT to conduct a structural analysis of other structural components. A straight-bladed VAWT in Yang Jiang, China, is used as a case study. The critical locations of fatigue and ultimate strength failure of the blade, shaft, arms, and tower are obtained.