The Mechanical Property of Magnetorheological Fluid Under Compression, Elongation, and Shearing

The mechanical properties of a MR fluid in compression, elongation, and shearing have been studied in the magnetic field which is generated by a coil carrying different magnitudes of DC electrical current. Test equipment is designed to perform this operation. The compressing tests showed that the MR fluid is quite stiff at small compressive strains being lower than 0.13. The compressive stress and modulus increase quickly when the compressive strain is higher than 0.2. The tensile yield stress of MR fluids represents the effect of the interaction force between the polarized particles and the direction of the applied magnetic field. The shear yield stress represents the effect of the interaction force with the shear direction (perpendicular to the direction of the magnetic field). The relationship between tensile yield stress and shear yield stress verifies the credibility of the calculation model employing a yield angle shaped between particles. A shear yield angle is found to be between about 13.8° and 16.9°, which agrees with the shear yield angle tested well by other researchers. The tensile yield stress is about four times of shear yield stress.