Application of laced built-up columns with cold-formed lipped angle sections in wind turbine towers

Abstract

Increasing the height of wind turbine towers effectively enhances their power output. Consequently, there is a growing demand for constructing wind turbine towers with higher hubs, especially in heavily populated and energy-intensive areas. Traditional approaches involve enlarging angled steel, posing production challenges and economic feasibility concerns. This study proposes replacing traditional angled steel with cold-formed lipped angles for improved structural performance. In this paper, a finite element model of the built-up column with cold-formed lipped angles is developed through ANSYS software. Finite element calculations are applied to various cross-sectional dimensions of cold-formed lipped angle sections to analyze column curves. Incorporating calculation methods from international standards, the paper presents a fitting formula and calculation method for the load-carrying capacity of the built-up column with cold-formed steel lipped angle sections. Finally, utilizing a wind turbine tower with a 120 m hub height as a case study, the paper conducts structural modeling and design analyses for both the built-up column with cold-formed lipped angles and the one with conventional angled steel. The research indicates that after adopting the built-up column with cold-formed lipped angle sections, the stress ratio of the tower columns is significantly reduced, with an approximate 16 % decrease in the stress ratio of the most critical section. The adoption of cold-formed lipped angle section effectively enhances the overall load-carrying capacity of the wind tower, providing a greater safety margin for the design. The calculation method provides valuable insights for future engineering applications.