Semi-active phase control of tuned mass dampers for translational and torsional vibration mitigation of structures

The present study aims at demonstrating the feasibility of semi-active phase control of tuned mass dampers (TMDs) implemented in structures for simultaneous reduction in translational and torsional vibration. The semi-active phase control, which employs a semi-active friction device, applies the friction force at certain situations to adjust the TMD phase back to the 90 degrees phase lag. Thus, the phase control tuned mass dampers (PC-TMDs) can develop the best power flow to reduce the structural vibration. In this paper, a complete phase control algorithm is proposed by considering a full range of phase differences. The proposed PC-TMDs not only improve the control performance but also prevent the TMD power from flowing back to the main structure. Furthermore, conventional suspension-type TMDs have only one tuning frequency and exhibit a potential off-tuning issue, lacking an ability to simultaneously suppress the structural translational and torsional vibration. The feasibility of application of the PC-TMDs is verified through various numerical simulations, and a practical mechanism for the PC-TMDs is introduced. The simulation results reveal the robustness of the PC-TMDs, particularly when the PC-TMDs are de-tuned to the structure. Therefore, the PC-TMDs outperform the conventional TMDs in terms of suppressing the structural responses in all the translational and torsional directions.