A Study on Vibration Suppression Devices Using a Giant Magnetostrictive Material

为了获得比被动减振器具有更好的减振效果的机械减振器，本研究开发了两种类型的滚珠丝杠减振器：一种是由滚珠丝杠、超磁致伸缩作动器、制动盘（铝盘）和闸瓦组成的半主动减振器；另一种是将半主动减振器和采用稀土磁体的滚珠丝杠磁性减振器结合在一起的混合减振器。制作了两种阻尼器，采用电液振动台测量了各阻尼器支承的简单梁（铜管）的地震反应。实验结果表明，输出速度反馈控制对抑制梁的最大挠度和减小阻尼器的阻力都是最有效的。在这种情况下，与不加阻尼器的情况相比，采用半主动阻尼器的梁的最大挠度减小到约1/18，采用混合阻尼器的梁的最大挠度减小到约1/70。然后，建立了采用混合阻尼器和螺旋弹簧隔震的3层建筑模型，并测量了基础隔震的建筑模型的地震反应。实验结果表明，该模型在3层处的最大加速度减小到非隔震模型的1/3 ~ 1/5。制作了一种由超磁致伸缩作动器和圆盘质量系统组成的新型激振器，并测量了激振器的频率响应。在本实验中，为了在30-100Hz范围内获得恒定的激励力，我们采用反馈控制的方式对激励力进行控制。结果表明，该激振器也可用于主动质量阻尼器。

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.