Research On The Mechanical Model Of Magnetorheological Shock Absorber In Vehicle Semi-active Suspension

Magnetorheological (MR) shock absorber plays an important role in the area of engineering application, and it is one of the most important components which influence the control effect in semi-active suspension system. Magnetorheological fluid (MRF) is the medium in MR shock absorber, and its rheological characteristics can be changed rapidly under the action of magnetic field. Comparing with the others controllable dampers, MR shock absorber has the trait of rapid response,low consumption,broad adjustable range and so on, so MR shock absorber of semi-active suspension has great potential in short-term industrialization and ascendant performance in projects. This thesis deduces the model of damping force in detail and builds up the finite element model (FEM) in ANSYS. Finally, based on the test data, further research has carried on the polynomial model. The text includes the following aspects:(1) This thesis introduces the basic theories of MRF based on working principle of magnetorheological effect and its main influencing factors. Built up a mechanical model based on working mode of MR shock absorber, and explained the deductive process in detail.(2) According to the design requirements of magnetic circuit, selecting the appropriate magnetic materials and MRF, figuring out the circle numbers by performance parameters of the materials. Analyzing the influence of parameters for damping force, optimal parameters have been figured out by optimal structure designing of MR shock absorber.(3) According to the physical model of MR shock absorber, FEM model of magnetic circuit has been built up by electromagnetism module in ANSYS software. Comparing with the scope of theoretical design, parameters'values have been ascertained. Hydrokinetics module can calculate the damping force. Obtaining the damping force - speed relation curves by analyzed the relations between parameters. (4) This thesis introduces and compares some mechanical models of MR shock absorber. Unknown parameters can be figured out according to fits the test results of MR shock absorber. Comparing the experimental values with polynomial fitting values, damping force - speed curves can be better identical. Current and piston's relative velocity influence the damping force of MR shock absorber, compare with theoretical calculation curve, polynomial model can describe nonlinear and hysteretic characteristics of MR shock absorber better.