Modelling the hysteresis phenomenon of magnetorheological dampers

Recently, magnetorheological (MR) dampers have emerged as a potential technology to implement semi-active control in structures and vehicle applications in order to efficiently suppress vibration. Perfect understanding about the dynamic characteristics of such dampers is necessary when implementing MR struts in application. One of the important factors to successfully attain desirable control performance is to have a damping force model which can accurately capture the inherent hysteresis behavior of MR dampers. Different models have been proposed to simulate the hysteresis phenomenon in such a kind of damper. The Bouc-Wen model has been extensively used to simulate the hysteresis behavior of MR dampers. However, considerable differences still exist between the simulation and experimental results. In this work, a methodology to find the characteristic parameters of the Bouc-Wen model in the attempt to better characterize the hysteresis phenomenon of MR dampers has been proposed. The methodology takes into consideration the effect of each individual term of the Bouc-Wen model over the hysteretic loop to estimate the appropriate values of the parameters. The Bouc-Wen model in which the new established characteristic parameters have been used has been validated against experimental data and an excellent agreement has been shown between the simulation and experimental results. Moreover, the findings pointed towards the fact that linear or exponential relationships exist between the estimated parameters and the current excitation. Considering this, a new model based on the Bouc-Wen model has been proposed in which the excitation current has been incorporated as a variable. This proposed modified Bouc-Wen model has also been validated against the experimental results and a good correlation has been found.