Review: A Survey on Configurations and Performance of Flow-Mode MR Valves

Abstract

Magnetorheological (MR) actuators are semi-active devices controlled by magnetic stimuli. The technology has been commercialized in the automotive industry or high-quality optical finishing applications. It harnesses the rheology of smart fluids to result in the unique application of the material. By a wide margin, the most common example of an MR actuator is a flow-mode single-tube housing with a control valve (electromagnet with a fixed-size air gap filled with the MR fluid) operating in a semi-active vibration control environment. The analysis of the prior art shows that the developed configurations of MR valves vary in size, complexity, the ability to generate adequate levels of pressure, and the interactions with the MR fluid’s rheology resulting in various performance envelopes. Moreover, miscellaneous testing procedures make a direct valve-to-valve comparison difficult. Therefore, in this paper we present a detailed and systematic review of MR control valves, provide classification criteria, highlight the operating principle, and then attempt to categorize the valves into groups sharing similarities in the design and performance envelope(s). Moreover, a simple performance metric based on the shear stress calculation is proposed, too, for evaluating the performance of particular valving prototypes. In the review, we discuss the key configurations, highlight their strengths and weaknesses and explore various opportunities for tuning their performance range. The review provides complementary information for the engineers and researchers with a keen interest in MR applications, in general. It is an organized and and critical study targeted at improvements in the categorization and description of MR devices.

Investigation the Effect of MR Fluid Composition on Properties at Low Strain Ranges

“…The main objective of the work included the assessment of the influence of selected components on one of the key properties of MR fluids, which is the yield stress. The value of this parameter is essential for almost all MR fluid applications, including shock absorbers, brakes, and valves [29][30][31][32]. The problem of determining limit stress values is a complex issue [33,34].…”

Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid

“…For devices working with MR fluids, the key aspect is a change in the apparent viscosity, observed as the ability to transition from a fluid state to a solid consistency. Control in the range of viscosity change is used primarily in vibration dampers [17] and controlled (measuring) brakes, while the control of fluid yield or flow stresses is particularly important for holding brakes [18], clutches [19] and valves [20,21].…”