Abstract
A compact annular-radial-orifice flow magnetorheological (MR) valve with variable radial damping gaps was proposed, and its structure and working principle were also described. Firstly, a mathematical model of pressure drop was established as well to evaluate the dynamic performance of the proposed MR valve. Sequentially, the pressure drop distribution of the MR valve in each flow channel was simulated and analyzed based on the average magnetic flux densities and yield stress along the damping gaps through finite element method. Further, the experimental test rig was setup to explore the pressure drop performance and the response characteristic of the MR valve and to investigate dynamic performance of the valve controlled cylinder system under different radial damping gaps. The experimental results revealed that the pressure drop and response time of the MR valve augment significantly with the increase of applied current and decrease of the radial damping gap. In addition, the damping force of the proposed MR valve controlled cylinder system decrease with the increase of the radial damping gap. The maximum damping force can reach about 4.72 kN at the applied current of 2 A and the radial damping gap of 0.5 mm. Meanwhile, the minimum damping force can reach about 0.67 kN at the applied current of 0 A and the radial damping gap of 1.5 mm. This study clearly demonstrates that the radial damping gap of the MR valve is the key parameter which directly affects the dynamic characteristics of the valve controlled cylinder system, and the proposed MR valve can meet the requirements of different working conditions by changing the radial damping gaps.
Highlights
The results show that the pressure drop adjustable range and response time of the disk MR valve are larger than those of the annular MR valve
Where ∆pa,η is viscosity pressure drop of annular damping gap, ∆pa,τ is field-dependent pressure drop with the change of magnetic flux density of the annular damping gap, ga is the thickness of annular damping gap, R is the radius of MR valve, th and La are the thickness of valve body and magnetic disk, respectively, τ y,a is dynamic shear stress of the annular damping gap, c is modification coefficient depending on the flow rate, and the value range is 2~3
In order to further explore the application of the proposed MR valve in industry, the annular-radial-orifice flow MR valve controlled cylinder system was proposed and set up, which were mainly composed of the double rod hydraulic cylinder, the hydraulic pipe, and the proposed MR valve
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In order to obtain better damping performance of the annular flow MR valve, it is necessary to increase the length of damping gap or the number of coils, which will expand the overall size and enhance the complexity of its structure. Simulation experiments were carried out by using different experimental design (DoE) techniques and ANSYS to obtain the regression model Both optimal results and initial results obtained from the constant relative permeability approximation magnetic circuit were compared. The magnetic flux density distribution and pressure drop in each liquid flow channel and the dynamic performance of the MR valve controlled cylinder system with four different radial damping gaps are analyzed. The pressure drop performance and response characteristics of the MR valves with different radial damping gaps are compared on the dynamic performance test rig. The proposed MR valve is connected to the valve controlled cylinder system as a bypass valve, and the dynamic performance of valve controlled cylinder systems is experimentally analyzed
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