A compressible magneto-rheological (MR) fluid damper with irregular MR valve

In this study, a prototype of compressible magneto-rheological (CMR) damper is designed, built, and examined. The CMR damper functions as a liquid spring and a controllable fluid damper in a single unit. The compressible MR fluid used in the proposed device is composed of 80wt.% of iron particle suspended in silicon oil. The CMR damper has an irregular annular MR valve with a flow path of varying cross section. This valve works in flow mode. The flow profile and pressure drops due to varying cross section of the flow path and different applied magnetic fields are studied from computational magnetic analysis. The experimental study of the CMR damper is performed. To evaluate the spring effect, experiments are carried out using pure silicone oil under different input displacements and frequencies. The spring effect of the liquid spring and the energy dissipated due to damping are obtained from the performance tests conducted with MR fluid for different input displacements at different frequencies and applied electric currents. The results are presented as force-displacement loops. To exhibit how the equivalent spring coefficient varies with input displacements, frequency of the motion and applied currents, the slopes of the force displacement loops are determined. To exhibit how the energy dissipated varies with input displacements, frequency of the input and applied currents, the areas of the force-displacement loops are obtained. From the values of the dissipation of energy, the equivalent damping coefficients are obtained. The values of the equivalent damping coefficients are compared with that of a CMR damper with a regular MR valve. The effect of the irregular flow path in the pressure drops for compression and rebound is presented.