Impact of increased particle concentration on magnetorheological fluid properties and their damping performance

Magnetorheological (MR) fluid properties are essential in analyzing the performance of any MR fluid system. The fluid properties are dependent on shape, size, and magnetic saturation of the magnetic particles. Preliminary characteristics with SEM, particle size analysis (PSA), and vibration sample magnetometer (VSM) on carbonyl iron particles were performed to verify the particle’s feasibility to synthesize the MR fluid in a laboratory. Synthesis and characterization of MR fluids with particle concentrations (PC) of 10% (PC₁₀), 15% (PC₁₅), 20% (PC₂₀), 30% (PC₃₀), and 35% (PC₃₅) by volume are carried out. To show the inherent nonlinearity of the MR fluid, Herschel–Bulkley model is used. The relationship between sedimentation velocity, yield stress, and thermal conductivity is established as a function of particle concentration with experimental uncertainty of 6.15, 5, and 8.96%, respectively. Functional testing of PC₁₅ and PC₃₀ was carried out on an MR damper fabricated on dimensions obtained from the literature for the required size. The results indicate that damping force is 42% more in PC₃₀ than PC₁₅ at higher loading parameters. Finally, the saturation magnetization of the MR fluid depends not only on applied current but also on loading parameters when operating in the system.