Influence of Initial Surface Roughness on Tribological Characteristics of Magnetorheological Fluid Based on Damper Design

Magneto-rheological (MR) damper is a specific type of semi active suspension component which have the nature of rapidly and reversibly changing the damping characteristics. During working process, magnetic particles in MR fluid would inevitably friction with cylinder and seal component. This paper aims to study the effect of initial surface roughness on tribological characteristics of MR fluid based on damper design. Los steel specimens with three different initial surface roughness were prepared and tested by using a pin-on-disc tribometer at various magnetic current, normal load and rotating speed. Friction coefficient was measured and recorded through the modified vertical universal friction and wear tester. Wear loss was calculated by measuring the weight of the pin before and after test. Three dimensional laser microscope was utilized to characterize the surface profile curves, surface roughness values and surface morphology of the specimens before and after tests. The wear mechanisms were analyzed and demonstrated through scanning electron microscope (SEM), coupled with an energy-dispersive X-ray spectroscope (EDS). The experimental results showed that the friction coefficient and wear loss of MR fluids not only affected by current, load and rotating speed, but also depended on the initial surface roughness. Because of the micro-size carbonyl iron particles in the MR fluid, the effect of initial surface roughness of specimens is more important.