| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Research Abstract |
In this research, two kinds of ball screw-type dampers have been developed in order to obtain mechanical dampers which are superior in the effects of vibration suppression to passive dampers : one is a semiactive damper consisting of a ball screw, giant magnetostrictive actuators, a break disk (an aluminium disk) and brake shoes, and the other is a hybrid damper which is united the semiactive damper and a ball screw-type magnetic damper using rare-earth magnets. Two kinds of dampers were made, and earthquake responses of a simple beam (a copper pipe) supported with each damper were measured using an electro-hydraulic type shaking table. The experimental results show that the case of the output velocity feedback control is most effective both for suppressing the maximum deflection of the beam and for reducing the resisting forces of the dampers. In this case, the maximum deflection of the beam decreases to about 1/18 by using the semiactive damper and to about 1/70 by using the hybrid damper compared with the case of without damper.
Next, a 3-story building model isolated by the hybrid damper and a coil spring was made, and the earthquake responses of the base-isolated building model were measured. The experimental results show that the maximum acceleration at the 3rd story of the building model decreases to 1/3-1/5 to that of the nonisolated one.
A new type of vibration exciter consisting of a giant magnetostrictive actuator and a disk-mass system was also made, and the frequency responses of the exciter were measured. In this experiment, the exciting force was controlled by feedback control in order to obtain a constant exciting force within 30-100Hz. As a result, it was confirmed that this exciter can be also used for an active mass damper.
|
