In-situ Capacitance Sensing for the Settlement of Magnetorheological Fluid: Simulation and Experiments

Abstract

In light of the insurmountable sedimentation of magnetorheological (MR) fluid, it is of great significance to ensure the performability of an MR damper by introducing a sensing method for MR fluid settling, and a key indicator to identify the health status of the MR damper is critical. However, the settling monitoring system for MR fluid can nowadays only function in a laboratory with transparent and non-magnetic tubes, which is not qualified for the in-situ sensing in a steel-made cylinder. Under the analysis of an open plate capacitor (OPC) configuration, the relationship between the concentration of magnetorheological fluid and the capacitance is investigated by simulation and experiments, and based on OPC, an in-situ sensing method for the settlement monitoring of magnetorheological fluid is designed. Long-time settling monitoring is carried out with home-made MR fluids, and the test results show that the sensing method can effectively reflect the status of settled MR fluids, and has the potential to be utilized in the identification of MR fluid compression points, which provides the strategic signal for the probable active or operational re-dispersing of MR fluid.