Evaluation of nonlinear dynamic phenomena in the hysteretic behaviour of magnetorheological dampers

The performance of a commercially-available magnetorheological (MR) damper is modelled via a one-way coupled numerical viscoelastic–viscoplastic approach. The approach adopts a Finite Element Analysis (FEA) of the magnetic circuit of the damper and a transient Computational Fluid Dynamics (CFD) analysis of fluid flow. The apparent viscosity of the MR fluid is defined as a function of the magnetic field intensity and local shear rate. The effects of different sources of the hysteretic behaviour of MR dampers, namely: fluid compressibility, fluid inertia, viscoelasticity and friction are investigated. Moreover, the effect of employing different rheological models in the numerical approach is investigated. The results indicate that that the effects of fluid compressibility and dynamic friction are the main sources of the hysteretic behaviour of the damper. Also, the results show the proper selection of the rheological model employed in the numerical approach is critical, as it leads to major differences in the predictions of the numerical approach.