Oscillatory normal forces of magnetorheological fluids

Abstract

The normal forces of magnetorheological fluids were investigated by a commercial magneto-rheometer with plate–plate geometry. Based on the analysis, it was found that the oscillatory normal forces can be achieved both under steady shear and oscillatory shear. The oscillatory normal forces obtained under steady shear developed from the nonparallelism of the testing plates, while the oscillatory normal forces under oscillatory shear mainly arose from the microstructure revolution of magnetorheological fluids. Finally, a dynamic simulation was utilized to analyze this oscillatory shear normal force and the formation mechanism was discussed.