Abstract: In order to investigate the magnetic field characteristics of a disk type shear yield stress measurement instrument,the magnetic circuit composition of the measurement instrument was introduced based on Ohm’s law of magnetic circuit and Ampere circuital theorem,and a simulation of the magnetic circuit is conducted in ANSYS firstly;moreover,the experimental analysis on the uniformity of magnetic field,magnetic flux density and measurement precision of the instrument is performed.The simulation result shows that the magnetic flux density in the working gap distributes uniformly and increases with the increase of the exciting current,the magnetic flux density in the working gap can reach 0.9T under the current 3.0A;the experimental results show that the shear yield strength measurement instrument can meet the needs of the measurement of magnetorheological fluid characteristic.

Key words: magnetorheological fluids, shear yield strength, measurement instrument, magnetic circuit