A Study of a Hybrid Damper Using a Lever-Type Displacement Magnifying Mechanism, Giant Magnetostrictive Actuators and Rare-Earth Magnets

摘要

In previous papers, the authors proposed two types of passive dampers using a lever-typedisplacement magnifying mechanism. One is a magnetic damper using rare-earth magnets and theother is a viscoelastic-friction damper using acrylic viscoelastic material.In this paper, a new type of hybrid damper using a lever-type displacement magnifyingmechanism, giant magnetostrictive actuators and rare-earth magnets is proposed. The hybriddamper generates controllable friction force together with magnetic damping force which acts as afail-safe mechanism in case of control system trouble, and is suitable for vibration in the region ofamplitude 0.1 ~ 10 mm. The trial damper was made and the resisting force characteristics weremeasured. The seismic responses of a three-dimensional piping system supported by the damperwere measured using an electrohydraulic type shaking table. The experimental results are comparedwith the calculated results obtained by the finite element method (ANSYS), and the effects ofvibration suppression of the hybrid damper are discussed. Moreover, these experimental andcalculated results are compared with those obtained for a semiactive friction damper (which is oneremoved the rare-earth magnets from the hybrid damper) and a passive magnetic damper (which isone removed the giant magnetostrictive actuators from the hybrid damper).