Abstract: Because the mathematical model of magnetorheological damper (MRD) isn't simple and accurate enough to reflect dynamic hysteretic behavior for engineering application, according to diverse actuating amplitude, frequency, current, a MRD prototype is tested for parameter identification and verification. Based on the test data the nonlinear dynamic behavior of MRD elastic, damping and current saturation characteristic is analyzed by variable actuating displacement, velocity and cur-rent when MRD is controlled with current or without current. To make the force-velocity curve smooth when the direction changes, neural network sigmoid transfer function is utilized integrating the test investigation, nonlinear viscosity-plastic model and simple nonlinear Bingham model. Also, the com-press and extension process is distinguished according to the accelerator direction as the nonliear bi-viscosity model. Based on mentions above the hysteretic behavior model of MRD is established. Then the physical meanings of several parameters for controllable damping force in model are studied. After iden-tifying the parameters in sigmoid hysteretic model, the control-lability of the parameters which affects the force-velocity hys-teretic loop slope and width is researched especially. The sig-moid hysteretic model is verified by experimental data finally.

Key words: Experimental analysis, Hysteretic behavior, Magnetorheological dampe, Mathematical modeling