Structural Behavior of Telescopic Steel Pipe for a Full-Scale 60 kW Wind Turbine Tower

A simple analytical model, including local effects due to buckling and shear to moment interaction, was developed to predict the load-carrying capacity of CHS tubes under flexure and shear. A finite-element analysis with ABAQUS Code was also conducted for validation of the proposed model. By properly modeling the imperfection effects due to the ovalization of steel tube, a good correlation of the structural response and failure mode was also achieved, and a good correlation with the analytical model was also achieved. Numerical and analytical results were compared with experimental results recently obtained by the author with good agreement. Experimental tests refer to full-scale static test to failure were conducted on 6 m length of steel pipe constituting a segment of a telescopic wind tower with a 60-kW wind turbine. The diameter of the circular cross-section of steel pipes was 900 mm and the nominal thickness 10 mm. Steel grade was S355 J2, according to Eurocode 3. Although local buckling caused slight strength degradation, the reduction due to shear to moment interaction was very significant, while the recorded response showed a good amount of post-buckling ductility although the ovalization of cross-sections.