ABSTRACT
The fundamental frequency is the key parameter in determining the dynamic response of the wind turbine tower. By theoretical derivation, this study proposed a method for calculating the fundamental frequency of the concrete-filled double-skin steel tubular (CFDST) onshore wind turbine tower. Based on the theory of the Euler-Bernoulli beam, the transverse free vibration equation of the wind turbine tower was established, which was a partial differential equation with variable coefficients. The method of energy equivalence was employed to solve the mentioned equation analytically. The frequency equation was solved by the method of series expansion. The effectiveness of the proposed method was validated by comparing it with the numerical simulation. A parametric analysis was conducted to investigate the effect of design parameters on the fundamental frequency. It concludes that the proposed method is effective and accurate in calculating the fundamental frequency of the wind turbine tower in the preliminary design.
