Behavior of Magnetorheological Fluids Employing Carrier Fluids Certified for Landing Gear Use

Magnetorheological (MR) fluids were prepared in order to investigate their performance for potential use in landing gear hydraulic systems, such as shock struts. MR fluids formulated here utilized three hydraulic oils certified for use in landing gear, two different average diameters of spherical magnetic particles, and a Lecithin surfactant. The fluids were characterized in order to measure and analyze their rheological behavior. Therefore, different characteristics were taken into consideration, such as 1) magnetorheology as a function of magnetic field, 2) cycling of a small-scale damper undergoing sinusoidal excitations at frequencies of 2.5 and 5 Hz, and 3) sedimentation analysis conducted with an inductance-based sensor. The goal of this research is to analyze the performance of these particular MR fluids, to compare their behavior to standard commercial MR fluids, and to determine their feasibility for use in helicopter landing gear.