Shaking table test on vibration control effects of a monopile offshore wind turbine with a tuned mass damper

To investigate vibration control effects of a tuned mass damper (TMD) on the monopile offshore wind turbine tower under wind-wave excitations and seismic excitations, shaking table tests on a 1/13-scaled test model equipped with or without TMD are implemented. The TMD device adopted in the test is a bidirectional TMD whose mass ratio and frequency ratio are properly designed. During the test, the model identification of wind turbine model is conducted via white noise sweep. Furthermore, the influence of aerodynamic damping generated by blade rotation on the dynamic responses of a monopile offshore wind turbine is analyzed. Additionally, the vibration control effects of TMD under different rotation speeds of the blades and various external excitations are intensively studied. Based on the test results, the seismic responses of a monopile offshore wind turbine attached with/without TMD are also analyzed by the finite element software ANSYS. It has been found that the results obtained by numerical simulation fit well to the results derived from the experimental tests, showing that the numerical simulation method proposed in this paper is feasible with satisfactory accuracy. Both experimental and numerical researches conducted in this work are conducive to the further application of TMD to offshore wind turbines that are situated in seismic active regions. It should be noted that the investigated time-histories cannot give a generalized result regarding the real performance of the TMD under wind-wave excitations. The documented results can only support an overview about the tendency of the TMD efficiency.