Magneto-Rheological Fluids in Squeeze Mode

Magneto-rheological fluids (MRFs) are suspensions of micron-sized ferromagnetic particles in a non-magnetic carrier fluid. The characteristic behaviour is the rapid and reversible transition from the state of a Newtonian-like fluid to the behaviour of a stiff semi-solid by applying a magnetic field. The MRF offers three modes of operation, the direct shear mode, the valve mode and the squeeze mode. To investigate the highly non-linear behaviour of the squeeze mode a test rig was designed for experimental purposes. Special emphasis was put on the dependence of the MRF response with respect to parameter variations of the applied static magnetic field, the cyclic loading amplitude and frequency values. Further, the cavitation phenomenon was investigated. Attempts to describe the squeeze mode phenomenon with FE simulations are presented. Furthermore, a MRF bearing with respect to industrial applications is presented. The substantial innovation is the rapid control of the radial load carrying capacity at low rotational speed. Analytical approaches to describing the load carrying capacity are shown. A promising field of application can be found in the field of rolling technologies.