Structural Analysis of Large-Scale Vertical Axis Wind Turbines Part II: Fatigue and Ultimate Strength Analyses

Abstract

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.

Structural Design Optimization of Laminated Composites for Vertical Axis Wind Turbine Blades: A Single Objective Approach

“…Ultimate strength analysis is considered for both normal and extreme conditions, while fatigue analysis depends on normal conditions. Other working conditions include startup, normal shutdown, and emergency stop (Lin et al, 2019b;Lin et al, 2019a). A numerical analysis of the VAWT H-rotor blade structure against extreme operation conditions is necessary to determine the material that can support maximum load (Hand and Cashman, 2020;Hand et al, 2021).…”

“…Rotor blades made of laminated materials exhibit competing fatigue modes, and their fatigue life depends on fabrication methods and environmental factors. Fatigue and VAWT life assessment are crucial for structural integrity and safety, especially in large-scale wind turbine design, where compressive loads cause more damage than tensile loads (Lin et al, 2019b;Lin et al, 2019a). Implementation of theoretical fatigue assessment method for HAWT 2 MW blades was conducted by (Liu et al, 2023).…”

Structural optimization using a genetic algorithm aiming for the minimum mass of vertical axis wind turbines using composite materials

“…This paper designs four different sizes of structural dimensions considering various output powers; the specific dimensions of each model are detailed in Table 1 . In this study, the blade is modeled using the NACA 0018 airfoil, selected due to its prevalent use in previous research [ 22 , 23 ] and the ready availability of aerodynamic coefficients [ 24 ]. The chord-to-length ratio of the blades, and the ratio of rotor diameter to blade length significantly affect the wind load and power output of the structure.…”

Structural Analysis of Large-Scale Vertical-Axis Wind Turbines, Part I: Wind Load Simulation

“…The wind pressures on the blade and the aerodynamic forces on the entire VAWT under the extreme wind speed are also required to conduct the ultimate strength analysis that will be presented in the companion paper [46]. In the case, the VAWT is standing still without rotating.…”