Abstract: The vibration of power generating units usually causes resonances in high-order modes of the powerhouse structure of a hydropower station and threatens its safety. Aiming at this issue, a vibration control method based on the tuned mass damper (TMD) is presented. A new type of high-frequency TMD controller is designed, and tests are conducted on the vibration reduction of a two-story steel frame, focusing on the damping effect under high-frequency harmonic excitation and narrow-band sweep excitation. The results show that this controller effectively controls the high order modes of the structure and its control effect is best when TMD-3 is added, achieving an attenuation rate of peak acceleration of 94.1% at the top of the structure, and 95.6% in the first layer. As the TMD tuning frequency is lowered from the high-order modes, the damping is decreased gradually, but its effect remains satisfactory. This indicates that the new TMD tuning frequency band is wider and has a certain robustness. For wider excitation frequencies, the damping effect is the best when the tuning frequency is close to the controlled frequency, but the robustness worsens when it deviates from the controlled frequency.

Key words: hydropower house, tuned mass damper, vibration reduction experiment, vibration control, high-order mode