Linearized state-space model of the behavior of MR-fluid dampers

Magnetorheological (MR) dampers are semi-active control dampers that use MR fluids to provide controllable damping characteristics. MR dampers have proven to be more effective than passive dampers in protecting civil structures during seismic events. While passive dampers have been thoroughly analyzed and understood by researchers, active and semi active dampers are still under investigation by many researchers. MR dampers added protection is achieved by adjusting the damping characteristics of the device so as to minimize structural dynamic loads. Models of the MR dampers highly nonlinear and difficult to adapt for active control, therefore, in this work, the MR damper model presented by Spencer et al will be solved numerically to obtain force-velocity data points. The data obtained from numerical solution of the damper model will be used to construct a linearized state-space model for control purposes. The state space model is obtained via system identification techniques and its agreement with the nonlinear model is discussed.