Influence of Design Parameters on the Ultimate Torsional Strength of Wind Turbine Tower Structure

Abstract As environmental issues become increasingly critical, the importance of renewable energy is being emphasized to achieve global goals such as Net Zero by 2050 and RE100. Wind energy, along with hydropower and solar energy, has emerged as one of the key renewable energy sources over the past few decades due to its efficiency. Wind turbine tower structures are required to meet strength requirements to withstand various load parameters, including torsional (e.g., torque due to blade rotation), laterally distributed (e.g., wind on the tower), laterally concentrated (e.g., wind on the rotor), and vertically varying (e.g., self-weight) loads. Due to their thin and tall structural characteristics, wind turbine tower structures may encounter issues where buckling and ultimate strength can occur under loads lower than the design limits. To achieve more robust tower designs, structural safety research on ultimate strength affected by the buckling and post-buckling behavior of the entire structure under these load parameters is essential. This study was conducted with the aim of identifying the influence of design parameters on the ultimate torsional strength and critical rotation of wind turbine tower structures. The key design parameters of the tower (length, bottom diameter, bottom/top diameter ratio, bottom thickness, and bottom/top thickness ratio) were determined with three levels (minimum, middle, and maximum) based on actual tower dimensions. A total of 243 models, created by combining the design parameters, were analyzed using the finite element analysis software ANSYS under fixed constraint conditions to evaluate the ultimate strength under upper torque. Using these results, a sensitivity analysis of the design parameters on ultimate torsional strength and critical rotation was conducted.