Abstract：A test method for rheological behaviors of MR greases based on double rotational coaxial cylinder shear mode is presented to obtain high shear strain rate and magnetic flux density. Both flow velocity profiles and shear stress profiles of MR greases in shear channels are analyzed. The theory relationship between shear stress acted on MR greases and transmission torques is established, the approximate algorithm is put forwarded to acquire nominal shear stresses of MR greases via transmission torques parameters. The relationship between shear strain rate and shear stresses is comprehensively established. On the basis of differential equation and its rational boundary conditions from stress equilibrium of MR greases micro-unit, the approximate algorithm is developed for nominal shear strain rates via rotor angular velocities. The relationship between average value of magnetic flux density in annular channels and excitation electrical currents are experimentally obtained. Based on the test method above, a rheometer is fabricated and modulated in Chongqing University, in which, torque sensor, angular velocity sensor and amperemeter are respectively used to test transmission torque, angular velocity and electrical current. Rheological parameters of certain MR grease by the rheometer, whose shear rate is more than 2000s-1 and magnetic flux density acting on MR greases exceed 0.6T, are in good agreement with those from the test with commercial rheometers.
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2010, Vol. 31 
