Experimental Verification of Semi-active Magnetorheological Dampers for Earthquake Structural Control

Magnetorheological (MR) dampers represent one of the most promising semi-active control devices for applications aiming at the seismic risk mitigation of new or existing civil structures. Two 30 kN MR dampers were experimentally tested subjecting them to assigned conventional displacement laws at their ends. The paper describes the main results of the above experimental activity and aims at improving the knowledge about mechanical and dynamical modeling of such devices. Three different phenomenological models are considered and compared one each other: a) an improved version of the Bingham model including the influence of the feeding current on the damping and friction force components; b) a widely adopted model, combination of viscous and elastic elements with an hysteretic part behaving as the Bouc-Wen law; c) a model superposing an hysteretic damper by a non linear viscous device. The simplicity of using each model, the influence of the involved parameters and the capability in fitting the experimental results are discussed herein.