Magnetorheological Fluid Device for Semi-Active Control of Hydraulic Damping

Abstract

The use of MR fluid offers a simple and direct control of the resistance force. Moreover, low energy consumption can be assured by battery and does not represent a danger for user. In the literature there are presented examples of the use of MR fluids for vibration damping but these examples aim at replacing the hydraulic fluid in the shock absorber with a MR fluid. The solution is viable but expensive compared to the price of passive type dampers (but cheaper than active damping) due to the use of a large volume of MR fluid. Another disadvantage of the solution presented above is the greater weight of the MR fluid device compared to the same hydraulic fluid device (the MR fluid density is much higher than that of the hydraulic fluid). Therefore, the aim of this paper is to presented a magnetorheological fluid device designed to control the damping force developed by a hydraulic shock absorber (magnetorheological piloted hydraulic damper). This type of damper (magnetorheological piloted hydraulic damper) has several advantages as: reduced cost due to the small quantity of magnetorheological fluid required, reduced weight compared to classical MR fluid dampers, aspect and overall dimensions similar to those of the passive damper and maintains the benefits of classical MR fluid dampers. Because the metal particles in the MR fluids tend to sediment, it is necessary to overcome the density of the fluid in applications where the staging time is high (seismic protection dampers). This monitoring is done with a PWAS device.