Modified Steel Tubes of Wind Turbine Tower Subjected to Compression-Bending Load

The wind turbine towers are essentially a multibody entity composed of rotor-nacelle assembly supported by a tubular tower that transfers the gravity load as well as the environmental load to the foundation. Several thin-walled steel tubes with flanges connected to form tubular steel towers. The records shows that most of the failure occurred at the bottom of the tube, and the major failure mode was local buckling. Thus, susceptibility to local buckling under compression and bending load accounts for the need for improved structural modification to the tubes of the wind turbine. The static analysis of innovative combined stiffened tubes was conducted by applying a constant axial force and varying lateral displacement. Different shapes of stiffeners, lengths of stiffeners, tubes with openings etc., were considered and the corresponding moment drift angle curve was generated. It was found that among all the considered specimens innovative modified steel tubes could greatly reduce the buckling deformation and increased both ultimate and failure loads. The static analysis of innovative combined stiffened tubes signifies a remarkable improvement in the ultimate moment of 42.85% was recorded and it was also found to be effective in controlling local buckling. The present study did not consider the connection between individual tubular units and residual stresses, apart from that modified steel tube was proven to be a feasible and efficient solution to control local buck-ling.