Performance Enhancement of MR Brake Using Flake-Shaped Iron-Particle–Based Magnetorheological Fluid

Abstract A non-spherically shaped iron particle–based magnetorheological (MR) fluid, particularly flake-shaped, is synthesized and utilized for the first time to evaluate the performance of an MR brake. The effects are compared with the commercially available spherically shaped particle–based MR fluid. The study shows that flake-shaped particle–based MR fluid with 70 % weight fraction of iron particles exhibits 17 % higher breaking torque at relatively low magnetic field strength compared to spherically shaped MR fluid with 72 % particle weight fraction. This increase in the torque value at low field is due to increases in the surface wetted area of flake-shaped particles. This enhances the friction between particle–particle and particle–carrier. Preferable to lower weight fraction requirement, the hysteresis loss is low and fluid has better stability in terms of gravity as well as thermally. The present MR fluid, having flake-shaped particles, improves MR brake performance substantially, both in terms of braking torque value at low field and reducing hysteresis loss. All the results are discussed based on the Herschel-Bulkley model. The performance of the brake is tested and evaluated in detail.