Development and Relative Assessments of Models for Characterizing the Current Dependent Hysteresis Properties of Magnetorheological Fluid Dampers

Magnetorheological (MR) dampers exhibit hysteretic and nonlinear force— velocity characteristics, which are strongly dependent upon the nature of the excitation and applied current. A number of reported models for characterizing such hysteretic and nonlinear force—velocity properties are reviewed in view of their applicability for predicting the hysteretic damping force under varying applied current and excitation conditions. It is concluded that the vast majority of these models lack consideration of damping force dependence upon the control current, and the frequency and magnitude of excitation. An independent current function is proposed that could enhance the current-dependent damping force prediction ability of the selected models, when integrated with the hysteretic force function. The parameters of the resulting modified models are identified on the basis of the measured data acquired for a MR-damper under wide ranges of excitation amplitudes and frequencies, and applied currents. These include modified linear biviscous, polynomial, extended Bouc—Wen and generalized sigmoid function models. The validity of modified models and the proposed current function is examined by comparing the model results with measured data under different currents and excitation conditions. The results show that the integration of the proposed current function could significantly enhance the performance of all models in predicting the current-dependent hysteretic damping force. The relative error analyses reveal that modified Bouc—Wen and sigmoid function models can provide reasonably good characterization of nonlinear and hysteretic MR-damping force over a range of current and excitation conditions considered in the study.