Development and Evaluation of a MR Damper With Enhanced Effective Gap Lengths

Abstract

Traditional magnetorheological (MR) damper featuring fixed gaps has the shortcomings of small damping force, single dynamic performance, and low adaptability. To overcome these shortcomings, a new MR damper with enhanced effective gap lengths is developed in this work, which achieves a double extension of the effective gap lengths via compactly integrating the conical fluid channels into the annular fluid channels. On the other hand, by altering the axial position of the valve spool controlled by a locking nut, the relative distance between the valve spool and piston of the MR damper is flexibly regulated; thus, the width of this adjustable gap in the conical fluid channels can be continuously adjusted. The magnetic circuit of the proposed MR damper is developed and its mechanical model is established as well to evaluate the dynamic performance. Sequentially, the finite element analysis (FEA) methodology is applied by using ANSYS/Emag software to investigate the changes of magnetic flux densities in these adjustable gaps. Moreover, a prototype is manufactured and experimental tests are conducted to verify its dynamic performance. The experimental results, under a fixed applied current, indicate that the damping force decreases with the increase of the adjustable gaps, and the maximum damping force reaches 7.2 kN at the adjustable gap of 0.6 mm. Besides, the dynamic range increases with the increase of the adjustable gap, and the dynamic range appears with a peak of 13.6. In addition, the damping force varies from 0.2 kN to 7.2 kN while the dynamic range attains 33 correspondingly by regulating the applied current and adjustable gap from 1.6 mm to 0.6 mm. From an experimental results perspective, the damping force and dynamic range can be not only effectively controlled by excitation current but also flexibly altered by regulating the width of the adjustable gaps simultaneously. Therefore, the dynamic performance of the proposed MR damper is also enhanced.

Magnetic Characterization of MR Fluid by Means of Neural Networks

“…Recently, the importance of these materials has been demonstrated in defining the interface between the electrical system and mechanics. MR liquids have applications in the mechanical (dampers, decelerators), automotive and aerospace (suspension, brakes, clutches), biomedical (dampers for prostheses) and construction industries (supports seismic) [7][8][9][10]. The advantage of MR materials compared to traditional materials is the ability to obtain damping without the need to vary the cross-sectional area, since the itself fluid controls the damping through a change in its viscosity.…”

Development and experimental characterization of a large-capacity magnetorheological damper with annular-radial gap

“…Researchers have designed, modeled, and prototyped MR valves with numerous configurations to develop MR dampers [18][19][20]. The MR valves, as the main part of MR dampers, generally consist of an electromagnetic circuit with a hydraulic channel [21].…”

Evaluation of flow-induced vibration suppression performances of magneto-rheological damping pipe clamp using PID algorithm

“…And the nonlinear hysteresis characteristics and magnetic saturation property of the CMR were studied in different current, amplitude, and vibration frequency. Hu et al (2020) developed a new type of magnetorheological damper enhancing the effective gap length and improving the hysteretic characteristics. Through the related experiment, the results showed that the damping force decreased with the increase of the adjustable gaps under a fixed applied current.…”