Simulation and investigation of magnetorheological fluid brake

The paper deals with coupled electromagnetic, hydrodynamic and mechanical motion phenomena in magnetorheological fluid (or simply MRF) brakes. The governing equations of these phenomena are presented. The numerical implementation of the mathematical model is based on the finite element method. Elaborated computer program is used to simulate the operation of MRF brake prototype. In order to verify elaborated algorithm and program, the investigation of the prototype of MR brake is carried out. The dynamic properties as well as mechanical and control characteristics of the brake are determined. The influence of MR fluid properties on functional parameters of the brake is also considered. Chosen results of simulations and measurements are presented.

I. Introduction

The characteristic feature of MRF is a dependence of their viscosity on magnetic field. A change in viscosity is inseparably connected with a change of yield stress in the fluid. The relationship between the yield stress and the magnetic flux density for MRF-132LD produced by Lord Corporation is shown in Fig. 1. The stress changes during the increase and decrease of magnetic flux density occur in microseconds [3], [6], [15]. The fluids retain their properties in the temperature range from-40°C to 150°C. The B-H characteristic for MRF 132LD is shown in Fig. 2. Relative magnetic permeability of the fluid is small, .