Finite Element Analysis of Post-Tensioned Concrete Wind Turbine Towers

Abstract

Wind turbines have seen a global increase in production by countries and energy developers trying to achieve renewable energy goals. Market demands have resulted in the development of larger turbines to produce more energy. Energy developers have been able to increase the energy production with two approaches. 1) Increasing the turbine blade length, which captures more wind, and 2) increasing the tower height which places the turbine blades higher into the atmosphere where there is stronger, more consistent wind. Wind turbines have been predominantly constructed with steel towers, which have been optimized to provide the most energy for the lowest possible cost. However, increasing the loading and height will require a larger turbine support structure. The current method of erecting a steel turbine tower is to fabricate the tower off-site and ship the pieces to the job site for assembly. With an increase in tower size to accommodate taller turbine towers, some tower sections may need to be split in half to meet shipping regulations. With the increase in tower height there is an increased difficulty in field fabrication and shipping, increasing the overall cost of the turbine tower. At around a tower height of 80 m (263 ft), concrete turbine towers start to become cost competitive with steel turbine towers [7]. The objective of this research is to analyze three post-tensioned concrete wind turbine towers in ANSYS to evaluate feasibility for use in towers above 100m. The towers evaluated will be 100 m (328 ft), 150 m (492 ft) and 200 m (656 ft) in height. Tower loading, geometry and material properties were obtained from a study published by NREL. The results of this study are meant to provide a basis for future wind turbine analysis in ANSYS of post-tensioned towers with specific design parameters.