Heating effects on magnetorheological dampers

Abstract

Over the past decades, scientists and engineers have tried to develop and improve various devices and control systems in order to mitigate and prevent civil structures against external dynamic forces such as strong wind and earthquakes. Indeed, damping devices absorb and dissipate the energy input during an earthquake, for instance and thus make structures safer and stable. Many types of devices are currently used such as viscous, friction or tuned mass dampers; however, one of the most recent promising systems proposed is the Magnetorheological damper (MR damper). Because of their ability to be controlled and to adapt their mechanical properties by varying a magnetic field, their high damping force (200kN), their low energy input required and their simple use and implementation in buildings, MR dampers seem to be suitable and realistic for civil engineering application. However, when they are subjected to external dynamic forces, the temperature increase in the damper device may significantly alter their performances and behaviors. This thesis first presents an overview of different technology control systems and MR damper device properties. Then, several mathematical models are developed and applied to explain the behavior of this class of damper. Finally, a study of the heating effects on MR damper performances incorporated in a real structure (3DOF) will be simulated.