Large-Scale Model Experiment of Hybrid Mass Damper with Convertible Active and Passive Modes Using Servomotor for Vibration Control of Tall Buildings.

Abstract

When normal active mass dampers using servomotors continue to work beyond the capacities of the servomotor systems, the servomotor drivers stop the motors to protect the motors and/or the drivers themselves against overheat due to overload. However, the hybrid mass damper developed can release the servomotors from the operation before their protection systems start to work, and can provide them with time to cool, while the mass damper continues to work as a passive mass damper ; then the servomotors can work again by mode switching from passive to active at the mass damper controllers' request. Shaking table tests were carried out for a large-scale experimental model of the hybrid mass damper with a 4 t moving mass supported by an XY-motion mechanism, and the driving mechanism in each direction consists of an AC servomotor of 5.5 kW capacity. The tests showed that the analytical models were obtained to express dynamic behavior of the mass damper in the active mode, the passive one and the mode switching. Simulations were carried out to predict performance against wind and earthquakes, where application of the model to a 7-story building was supposed. The results showed that the hybrid mass damper had good performance throughout a wide range of excitation intensity.