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

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.