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

Abstract

Large-scale model experiments were carried out to examine the feasibility for practical use of a hybrid mass damper with convertible active and passive modes using a cylindrical linear induction motor. This mass damper can function as an active one to control relatively small vibrations of tall buildings caused by winds and weak earthquakes, and can also function as a passive one against strong earthquakes. By using the linear motor as an actuator, the mass damper can perform the mode switching simply by turning the power off and on, although its power efficiency is worse than that of dampers using normal AC servomotors. Shaking table tests were carried out for a one-dimensional experimental model having a 4.3 t moving mass equipped with two linear motors each of 7.6 kW capacity. Through the tests, validity of analytical models for the active mode, the passive mode and the mode switching was confirmed. Simulations were also carried out to predict performance of the experimental model when it was applied to a 7-story building, and showed excellent performance against strong winds and moderate earthquakes.