Abstract

Abstract
Control systems play a crucial role in the operation of airplanes, robots and the new generation of smart automobiles to improve their performance, safety and robustness. Considering the ability of control systems to optimize the functionality of damping devices, such controllable devices can effectively dissipate the seismic vibrations of structures in which they are installed. Although dampers are utilized in many structures, the main issue is that most of such devices function in passive mode without control systems. In some cases, such passive damping systems may perform inefficiently and cause detrimental effects which may endanger the safety of the structures. Magnetorheological (MR) damper is a type of semi-active damper that produces variable resistant force according to the intensity of the magnetic field which is induced by a direct electricity current (DC). Since direct current can be supplied by batteries, this type of damper is functional and serviceable in harsh conditions in which the power supply may be interrupted. Therefore, the capability of variable force production demanding less energy is the major advantage of MR dampers. In this research, seismic response of a 2D single-story structure which is equipped with an adaptive MR damper is investigated and a fuzzy control system is added to the damper to smartly control and adjust its performance in real time. The fuzzy controlled system adjusts the applied electric current to the damper according to the displacement response of the structure caused by an earthquake. Therefore, it makes the resisting damper force proportional and adaptive to the magnitude of the earthquake forces. The analytical results illustrate that such controllable damping system can effectively dissipate the seismic vibration of the structure subjected to two sets of far-field and near-field (pulse- like) earthquake records. In this way the average of the maximum seismic demands in the dynamic model including wave energy, acceleration, velocity and displacement decrease by 38%,40%,36% and 83% for far-field records and by 40%,43%,40% and 82% for near-field (pulse-like) records respectively.

Keywords: MR damper, fuzzy logic, mamdani system, seismic loads, energy dissipation