Finite element based modeling of magnetorheological dampers

Abstract

For an efficient damper design, a design engineer always faces the challenge of providing the largest forces in the most compact and efficient envelope. It is important to identify the nature of the force required at the output in order to configure the damper to produce more force in less space. This thesis takes into consideration the role of MagnetoRheological (MR) fluids played when used in conjunction with dampers. In order to achieve this purpose, a finite element model is constructed to analyze and examine a 2-D axisymmetric MR damper. The results obtained in this thesis will help designers to create more efficient and reliable MR dampers. With the help of finite element tools, some design analyses are created to change the shape of the piston in the damper or other parameters in the model. The main benefit of this research is to show a 2-D MR damper and generate the magnetic flux density along the MR Fluid gap. The magnetic saturation is detected by looking at the nodal solution for the magnetic flux density. Increasing the current in the model, results in an increase in magnetic induction. Three different configurations of an MR damper piston were studied in order to determine how changing the shape of the piston affects the maximum force which the damper provides. The variations provided in the MR fluid gap were plotted for magnetic flux density contour before and after reaching the rheological saturation. By increasing the current, the color spectrum of the magnetic flux density will shift from the MR fluid gap to the piston centerline. As the current provided to a reasonably good amount, the force obtained was to a good extent. But it reaches saturation at around 2 amps. Thus for constraint or heat build up limitations, the second model could work the best among the three designs that we considered. For cases where higher electrical currents can be tolerated, model 2 would be the most advantageous design, since it provides the largest force among the three models.