Analytical and experimental validation of a nondimensional Bingham model for mixed-mode magnetorheological dampers

In this paper an experimental validation of a nondimensional analysis for a mixed-mode magnetorheological (MR) damper is described. Based on the Bingham constitutive equation of an MR fluid, a nondimensional model describing damping capacity of the MR damper is formulated using nondimensional parameters including the Bingham number, nondimensional plug thickness, hydraulic amplification ratio, and equivalent viscous damping coefficient. The effects of the Bingham number and the hydraulic amplification ratio on the nondimensional plug thickness and equivalent viscous damping coefficient are analyzed. A mixed-mode MR damper is designed and fabricated to validate the relationships between nondimensional parameters. The damper is tested under various loading conditions and current (applied magnetic field intensity) levels. The nondimensional parameters and variables are measured experimentally, and the effectiveness of the nondimensional analysis model for mixed-mode MR dampers is demonstrated. In addition, comparisons between mixed and flow mode dampers are undertaken using this nondimensional analysis.