Phase Controlled Semi-active Tuned Mass Dampers for Vibration Reduction under Base Excitation

Phase Controlled Semi-active Tuned Mass Dampers for Vibration Reduction under Base Excitation

The vibration suppression effect of phase controlled semi-active tuned mass dampers(SATMD) under base excitation is proposed in this study. The phase control algorithm applies the variable friction force to slow down the mass block at specific moments when the phase lag of the SATMD with respect to the structure is off the optimal 90 degrees, returning the SATMD back to the desired phase lag, i.e., a -90 degree phase deviation, so that the SATMD has maximum power flow to reduce the structural vibration. A single-degree-of-freedom structure with phase controlled SATMD is simulated to be subjected to sinusoidal base acceleration, random base acceleration, and earthquakes. Under the sinusoidal base acceleration, the results show that the SATMD has a broader range of excitation frequency in reducing structural vibration than the optimal passive tuned mass damper. The SATMD also has better robustness of its design parameters especially the frequency ratio under random base accelerations. The earthquake excitation shows that although the SATMD is not very effective in reducing the peak value of structural response but it is still able to reduce root-mean-square responses.