Generalized model of a magnetorheological fluid damper for fluctuaiting magnetic fields

The paper investigates a generalized model of a magnetorheological fluid damper (MRD). Rheological behaviour of MR fluids is described and so is the Spencer model taking into account the effects of magnetic field fluctuations in the MRD gap on the magnitude of damping force. It is demonstrated that the Spencer model does not fully emulate the real behaviour of the MRD, especially at low current levels. Some modifications of the model are suggested, whereby a nonlinear function is introduced, enveloping the family of damping force curves. The thus formulated generalized model is then verified experimentally. The model efficiency is confirmed by investigation of MRD control in a semi-active vibration isolation system for a quarter car body.