Magnetic field dependent electric conductivity of the magnetorheological fluids: the influence of oscillatory shear

• Published in: Smart materials and structures Vol. 26; no. 3; pp. 35067 - 35077
• Main Authors: Ruan, Xiaohui, Wang, Yu, Xuan, Shouhu, Gong, Xinglong
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.03.2017
• Subjects: electric conductivity; magnetic field; oscillatory shear; particle-particle resistance model; semi-empirical formula
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/1361-665X/aa5fe5

In this work, the influence of oscillatory shear on the magnetic field dependent electric conductivity of the magnetorheological fluid (MRF) was reported. Upon applying a 0.96 T magnetic field, the electric conductivity could increase about 1500 times larger than the one without magnetic field. By increasing the volume fraction of carbonyl iron particles in the MRF from 5% to 30%, the electric conductivity increased about 565 times. Under applying an oscillatory shear, the resistance of the MRF decreased and it oscillated synchronously with the oscillatory shear. Interestingly, the larger shear strain led to larger oscillatory amplitude of the resistance. A particle-particle resistance model and a semi-empirical formula were proposed to investigate the influence of the oscillatory shear on the electric conductivity. The fitting results matched the experimental results very well. At last, a possible mechanism was proposed to explain the changes of resistance.