Structure Design And Performance Analysis Of Improved And Typical Radial Type Magnetorheological Valves

In general,the performance of a valve can be determined mainly by its capability to create and regulate pressure drop,the pressure drop in the valve area can be augmented by changing the flow channel structure or extend the length of the flow channel.In the three typical liquid flow path structures,when the volume is constant,the hybrid flow structure can achieve greater pressure drop and adjustable range,followed by radial flow structure,annular flow structure.The existing hybrid flow path is achieved by a composite coil structure,while this approach will lead to larger size and higher weight of MR valve.In order to solve this problem,this paper presented an improved radial type MR valve which twists the magnetic flux path into the unexposed annular gap by adding parts and changing the material properties of the typical single radial type MR valve.This design helps to increase the additional annular effective areas and without having to increase neither the valve dimension nor the length of flow path,so that the improved valve with serpentine flux path can achieve the effect of the hybrid flow MR valve and further increasing the pressure drop.The main research contents of this paper include:1.An improved radial type MR valve with serpentine flux path was presented by reasonably adding parts and changing the material properties of the typical single radial type MR valve.Choosing suitable material for each part and deducing the magnetic circuit model for typical and improved radial type MR valve,respectively,then the theoretical magnetic flux density at effective resistance gap were derived.The flow paths of two kind of radial type MR valve are divided and the pressure drop models were established in accordance with the yield pressure drop and the viscous pressure drop,respectively.2.The finite element method(FEM)was used to investigate the effects of material properties on the magnetic flux distribution and pressure drop change in the improved and typical radial type MR valves under the same geometry conditions and the same flow path,in which the pressure drop under different applied currents and different flow rate was obtained.Finally,the theoretical magnetic circuit model and simulation model are compared to verify the rationality of the structural design.3.The improved and typical radial type MR valves were processed and assembled.The dynamic performance test of MR valve is designed and built,and the labview programming software was used to complete the date acquisition function.The pressure drop and transient response characteristics under different applied currents and different flow rate of the improved and typical MR valves were tested and analyzed respectively.It is analyzed whether the performance of the improved MR valve is superior to that of the typical MR valve,and the rationality of improved structure is verified.4.Two types of bypass valve-controlled damper systems with different damping forces were respectively formed by incorporating the improved radial type MR valve and typical radial type MR valve into the single-ended hydraulic cylinder with a bypass duct.The damping characteristics of two types of bypass valve-controlled damper systems were tested by INSTRON fatigue stretcher respectively.And the effects of different current,amplitude and frequency on the output damping force were also studied.