International Review of Mechanical Engineering (I.RE.M.E.), Vol. 17, N. 6 ISSN 1970 - 8734 June 2023 Copyright © 2023 Praise Worthy Prize S.r.l. - All rights reserved https://doi.org/10.15866/ireme.v17i6.23465 248 248 Performance Assessment and Optimization Studies of a Modified MR Damper Prototype Yashpal M. Khedkar 1 , Sunil Bhat 2 , H. Adarsha 3 Abstract – 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. Copyright © 2023 Praise Worthy Prize S.r.l. - All rights reserved. Keywords: Magnetorhelogical Fluid (MR Fluid/MRF), Magnetorheological Damper, Vibration Control, Damping Force, Force-Velocity Characteristics Nomenclature β Regression coefficient ER Electrorheology f Frequency [Hz] F Force [N] Ie Excitation current [A] MF Magnetic flux density [T] MR Magnetorheology MR damper Magnetorheological damper MR fluid Magnetorheological fluid QC Quality Characteristics T Magnetic flux density [T] v Velocity [mm/s] Wx Weight percentage with response measure x Wy Weight percentage with response measure y x Response measure for velocity xmax Maximum response measure for velocity xmin Minimum response measure for velocity y Response measure for force ymax Maximum response measure for force ymin Minimum response measure for Force I. Introduction Engineers and academicians have found out that the vibration control technology is a challenging subject of study. Excessive vibrations have remained an issue for civil structures, automotive systems, industrial equipment, and so on. Off late, new types of vibration control systems like Magnetorheological dampers (also known as MR dampers) have been deployed to dampen excessive vibrations on a variety of fronts. Instead of using basic damper oil, MR damper uses a fluid called MR (Magnetorheological) fluid. Electro-Rheological Fluid (ER) and the Magneto-Rheological Fluid (MR) are two types of smart fluids. The dampers used with these fluids provide high damping with minimal power consumption. The carrier liquid and the freely floating ferromagnetic particles are in the proper proportions in the MR fluid. In the absence of magnetic field, MR fluid behaves like regular damper oil (OFF state condition). However, the freely suspended ferromagnetic particles produce a chain-like structure, which quickly counters and dampens the vibrations, as soon as electric power is supplied to the MR damper. This state is known as the