Magnetic Circuit Analysis and Fluid Flow Modeling of an MR Damper With Enhanced Magnetic Characteristics

Abstract

A novel design of a magnetorheological (MR) damper is developed, fabricated, modelled and tested. The design includes some features that enhance the magnetic characteristics of the damper. The iron-cobalt-vanadium "Vacoflux-50" alloy and the "AMT-Smartec + " MR fluid, whose magnetic characteristics have been predicted to enhance the performance of the damper, are employed in the new design. Moreover, the location of the MR fluid region in the piston construction has been chosen so that the magnetic field maximises. To evaluate the impact of the proposed design improvements, an approach to modelling the performance of a previously-tested MR damper of a different design, different magnetic material, and different MR fluid has been developed. The approach combines a Finite Element Analysis (FEA) of the magnetic circuit, and a nonlinear analytical model of fluid flow. The results of the FE/analytical approach have been validated using the available published results of the same damper. Hence, the approach has been used to predict the performance of the same damper due to the employment of the proposed design improvements. The FE/analytical approach accounts for the nonlinear characteristics caused by the magnetic saturation of materials and the effects of fluid compressibility and aeration in the damper. It has been found that the implementation of the proposed design features leads to a remarkable increase in the magnetic field and the fluid yield stress. Also, the inclusion of the nonlinear magnetic and fluid flow characteristics have been found to affect the magnetic field distribution and the fluid yield stress greatly.

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

“…The former has a unique feature of intrinsic asymmetric ∆P − Q envelopes in either direction of motion (achieved due to different flow losses) whereas the latter shows the annulus shifted below the coil window. Despite certain advantages [77], it can be argued that the valve in Figure 7c may be more liable to saturation. Moreover, the gap's smaller circumferential width (compared to the benchmark valve) may translate into steeper slopes of the ∆P − Q characteristics.…”

“…The original concept [66] shows the flow path above the coil window. In the view of [77], shifting one or both flow channels below the coil window (see Figure 7h) would be possible with all the consequences this particular configuration supplies.…”

“…MR valves: configurations, 1-core, 2-coil(s), 3-primary flow path(s), 4-ring, 5-bypass, 6-(non-magnetic) spacer ring, 7-permanent magnet. (a) Benchmark valve [24,25]; (b) Variable height [69]; (c) Annulus location [77]; (d) Bypass valve[59,60,78,79]; (e) High active area ratio[80]; (f) Fail-safe valve[81]; (g) Dual annulus (concentric)[66]; (h) Dual annulus, adapted from[66,77,82].…”

Design and experimental research of stepped bypass magnetorheological damper

“…A new magnetorheological damper using an iron-cobalt-vanadium ''Vacoflux-50'' alloy and an ''AMT-Smart ec + '' MR fluid was used to comparatively model the performance of magnetorheological dampers with different magnetorheological fluids. A significant increase in magnetic field and fluid yield stress was found (Elsaady et al, 2020). In order to solve the disadvantages of complex coil structure and high manufacturing cost of most magnetorheological dampers, magnetorheological dampers with simple structure and new magnetic circuit with separate positioning of the piston head were designed.…”

Fuzzy Sliding Mode Control of Vehicle Magnetorheological Semi-Active Air Suspension

“…As a new type of intelligent semi-active control device, the MR damper has become a research hotspot and can be well applied to semi-active air suspension, due to its good performance, i.e., simple structure, controllable damping force, low power consumption as well as rapid response time [6][7][8][9]. In industrial application, the accurate establishment of the mathematical model of MR damper is an important step for the design and analysis of the semi-active controller.…”