Dynamic Physical Model for MR Damper Considering Chain Deflection in Preyield Stage

Abstract

A novel dynamic physical model for a magnetorheological (MR) damper is proposed. In this model, the hysteretic properties are considered to result from the difference between the working mechanism of MR fluids in their preyield and postyield stages. In the preyield stage, the MR damper’s force is caused by the chain deflection of MR fluids, which can be described by a particle-chain model. However, in the postyield stage, the MR damper’s force is caused by the flow gradient of MR fluids, which can be accurately predicted by the quasi-static model. Therefore, the proposed model is a combination of a particle-chain model and quasi-static model. The input-current dependence and loading-condition dependence of MR damper are then addressed. By establishing the relationship between model parameters and input current, the input-current dependence is solved. By analyzing the physical mechanism of the proposed model and its consistency with experimental data, the relevance with the loading amplitude and frequency is revealed. For the purposes of validation, comparative studies between the proposed physical model and phenomenological models such as the extended Bouc-Wen model under different loading conditions are carried out. Numerical results show that the proposed model produces a highly accurate description on MR damper’s hysteretic properties and maintains better robustness for the cases with various loading conditions. Also, the dilemma between accuracy, robustness, and complexity inherent in traditional phenomenological models can be elegantly solved by the proposed physical model.