Nondeterministic Dynamic Analysis and Structural Optimisation of the Steel Towers Design for Wind Turbines Support

This research work aims to perform a structural optimisation of a steel tower used to support a 2 MW wind turbine, considering the natural frequencies, stresses, buckling resistance, and displacement constraints, to reduce the volume of steel required for the structure. The investigated structure is modelled based on the use of a three-dimensional finite element model that includes the soil–structure interaction effect, the rotor loads and the wind nondeterministic effect acting on the steel tower. Due to the nature of the mathematical formulation presented for the dynamic effect of the wind, a statistical analysis of the dynamic response of the structure as well as the results of the nondeterministic optimisation is performed to obtain the results within a 95% confidence level. Based on the obtained results, it was shown that the optimisation process considering the dynamic nondeterministic effect of the wind leads to a project, the volume of which is 31.5% lower than the original volume and only 4.5% higher than the project obtained considering its static effect. However, it was concluded that taking to account the wind nondeterministic mathematical formulation, the optimised steel tower structural design presents greater robustness to uncertainties associated with the numerical modelling of the wind loadings.