A Design Theory Discussion Of Magneto-Rheological Shock Absorber Used In The Semi-Active Suspension System Of Vehicles

Because traditional vehicle suspension systems have become increasingly unable to satisfy to the safety and comfort requirements, the development can satisfy the requirements of the intelligent suspension system shock absorber, suspension system at the moment the best damping effect become an important issue. Magneto-rheological fluids (MRF) as an smart material with good rheological properties, becomes semi-active suspension system shock absorbers first choice material.This disquisition introduced the magneto-rheological fluids, analyzed the rheological effect and rheological mechanism of magneto-rheological fluids, and analyzed three models of magneto-rhelogical shock absorbers, according to the vehicle suspension system features, this disquisition used shear flow pattern combinations of a magneto-rhelogical shock absorber to take a design basis. Based on knowledge of hydrodynamics, set up a magneto-rheological fluids under no magnetic field of mathematical models and a magnetic field of mathematical model, according to Newton and Bingham fliuds constitutive equation and combination modes structure of shear and flow, derived damping force formulas of the magneto-rheological shock absorber under two fluid states. Meanwhile, according to the work requirements for the vehicle shock absorber, this disquisition carried on the discussion that designed the respect of the theory to the magnetic circuit and structure of the magneto-rheological shock absorber. From the damping force formula, we can see that the damping force is not only structure parameters , such as an area of the piston, the cylinder diameter, the damping gap size, damping channel length, etc., but also with dynamic parameters, such as the magneto-rheological fluids viscosity, yield shear strength, piston speed etc.. Yield shear strength and the electricity coil magnetic induction corresponds to the relationship coil energized the magnetic induction with both current correspond with the size of the linear relationship so by changing the coil current size, can instantaneous damping force control of the size, to achieve the objective of reducing vibration. In the vehicle suspension dynamic performance simulation test platform, have made the texts to the 1005-3 magneto-rheological shock absorber of Lord Company, the tests include dynamic response, work said the characteristics, speed characteristics and temperature characteristics, and the design theory can explain the good test results, so this vehicle semi-active suspension magneto-rheological shock absorber design is a reasonable theory, Damping is derived formula is consistent with the requirements of the shock absorber design, It has certain academic value of theory and directive significance to the design semi-active suspension system magneto-rheological shock absorber of voluntarily vehicles.