earticle

영어

This paper aims to propose a brake unit driven by magnetorheological fluid together with shape memory alloy, based on the shape memory effect of shape memory alloy under thermal effect and the rheological behavior of magnetorheological fluid. The Bingham model is used to describe the constitutive characteristics of magnetorheological fluid subject to an applied magnetic field to derive the braking torque equation of brake induced by magnetorheological fluid. Based on the shape memory effect, the relationships of the shape memory alloy spring’s output force with the temperature, the geometric parameters, the material parameters and the operating load is established to derive the braking torque equation of brake induced by shape memory alloy. The expression of the braking time is obtained from the torque-equilibrium equation of the braked shaft. The results indicate that the output force of the shape memory alloy spring can change rapidly with the temperature. The braking torque developed by shape memory alloy is increased with the increase of temperature. With the increase of the applied magnetic field strength, the braking torque developed by magnetorheological fluids goes up rapidly, and the braking time is shortened.