Design and analysis of a semi-active damper with mangnetorheological fluid

Semi-active controllable devices with MR fluid which have drawn significant attention especially in transportation vehicle, building suspensions and biomedical applications in the last two decades owing to their unique advantages.In the study, a new dynamic model based on Bouc-Wen model was proposed. Nonlinear hysteresis behaviors of a MR damper could be modeled by this dynamic model. We modified the Model equation by substituting the model parameters in the proposed forms to generate an equation that is only current dependent for control applications.In this study also, fluid flow in MR damper which occurred by piston movement was modeled by using a commercial computational fluid dynamics (CFD) code and flow quantities were obtained for during a piston cycle. In the CFD model, nonlinear region that is under magnetic field in gap was described with piston movement thus it was provided exact similarity with physical condition. In addition to this, a commercial electromagnetic analysis code was used to estimate magnetic flux densities.The study deals with also the optimal sizing of the MR dampers using Taguchi design of experiments method and optimum damper geometry was obtained by the method. Moreover, numerical solutions of magnetic field analysis and fluid flow analysis were used to estimate optimal damper geometries for determined target values.Nine candidates damper determined according to Taguchi method were fabricated and tested. Experimental results compared to both numerical and analytical results. Experimantal data was used to estimate parameters of dynamic model.