Performance Assessment and Optimization Studies of a Modified MR Damper Prototype

Vibrations are known to cause problems in many automotive systems and industrial equipment. Therefore, vibration control devices such as traditional hydraulic dampers are used to minimize the vibrations. Off late, MR dampers, in which MR fluid is used to enhance the vibration reduction performance, are introduced. An electromagnetic piston is positioned within the MR damper cylinder that creates the magnetic field necessary to operate the MR fluid. However, due to the internal electromagnetic piston arrangement in the conventional MR damper, some serious issues like remenance phenomenon, clumping and heat effect are observed. Consequently, a modified MR damper with an external permanent magnet assembly is proposed. Viability of modified MR damper concept is checked vis-à-vis conventional MR damper. After a successful check, a handy prototype of the modified MR damper is fabricated. The performance of the modified MR damper prototype is tested by changing the MR fluid configuration, the excitation frequency of exciter, the excitation current, and the magnetic flux density. A test rig is designed and fabricated for this purpose. The MR effect on velocity and damping force in the prototype is recorded and the observations are utilised in performance optimization. The Overall Evaluation criterion is employed in the optimization process with MR fluids of 76%, 80% and 82% weight percentage of ferromagnetic particles (AMT-Dampro, AMT-Magnaflo and AMT-Smartech MR fluids respectively). The regression analysis for most suitable MR fluid configuration is also undertaken. The modified MR damper prototype is found to work effectively as confirmed by optimization and regression analysis results. The idea of the modified MR damper can be suitably applied to number of existing practical systems to handle intense vibrations.