Experimential Research on the Dynamic Characteristics of Wind Turbine Support Structures Using Vibration Table Model

In order to study the dynamic characteristics of the support structure of an offshore wind turbine （OWT）， a 1∶15 scaling model was designed for a 6.45 MW offshore single-pile wind turbine with a height of approximately 135 m. The similar design was carried out based on dimensional analysis， and the additional mass was designed in the form of “counterweight platform +counterweight block” to meet the similar stiffness. The effective length of the embedded steel pipe pile was determined using the equivalent embedding point method， and the dynamic characteristics of the tower structure were tested by applying a predefined displacement excitation along with bidirectional white noise input at its base. The test results showed that the damping ratio of the tower model was 0.67%， demonstrating low inherent structural damping. The experimental frequency was close to that of the prototype. Furthermore， the normalized mode shapes of the model and the full-scale structure showed good agreement， thereby validating the scaling method as reasonable and effective. The acceleration response at the tower top exhibited a distinct "beat vibration" phenomenon. This indicates that the highly flexible and slender structure produces torsion under the action of horizontal outward-excitation.