The influence of magnetic hysteresis on magnetorheological fluid clutch operation

Purpose - The purpose of this paper is to elaborate upon the mathematical model of coupled electromagnetic, fluid dynamic and motion phenomena that will allow for investigation of the magnetic hysteresis influence on the axial symmetry magnetorheological fluid (MRF) clutch operation. Design/methodology/approach - To solve the partial differential equations describing magnetic vector and fluid velocity potential distributions in axial symmetry MRF electromechanical transducers the finite-element methods have been applied. To solve model equations in the time domain, the time stepping method have been adopted. To introduce magnetic hysteresis phenomenon to presented approach the Jiles-Atherton model have been applied. The physical properties of MRFs have been modeled by means of the Bingham model. Owing to high nonlinearity of the considered problem to solve obtained matrix equations systems the iterative Newton-Raphson combined with the block over relaxation method have been applied. Findings - The proposed model of coupled phenomena and the elaborated algorithm for solving the nonlinear model equations can be successfully applied in the analysis of transients in the MRF transducers taking fluid dynamics and magnetic hysteresis into account. Comparison of the measured and calculated clutch characteristics proves the model accuracy. Moreover, it has been shown that the residual magnetic flux density of the ferromagnetic core has significant impact on both to yield stresses forming in MRFs as well as the torque in disengagement clutch operation. Originality/value - Development of the method for analysis of transients electromagnetic and fluid flow phenomena in MRF transducers taking magnetic hysteresis, electric circuits and motion into account. The presented approach is universal and can be successfully applied in other types of MRF electromechanical transducers such as clutch, brakes, rotary and linear dampers.