2019
Volume 19, Number 3/4, pp. 80-85
Rheological properties of magnetized bidisperse magnetorheological fluids containing needle-like particles
Yuhiro Iwamoto,1 Tomoki Koroki,1 Yasushi Ido,1 Hisashi Yamamoto,2 Hitoshi Nishida,2 Yasuhisa Fujii3 and Tomoe Deguchi3
1 Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
2 Department of Electrical and Control Systems Engineering, National Institute of Technology, Toyama College, 13 Hongo-cho, Toyama 93908630, Japan
3 KRI, Inc. Kyoto Research Park, 134, Chudoji Minmi-machi, Shimogyo-ku, Kyoto 600-8813, Japan
There is widespread interest in magnetorheological fluids because their viscoelastic properties substantially change upon application of an external magnetic field. This effect is often called a magnetorheological effect. We here propose a new approach to achieve a higher magnetorheological effect, namely premagnetization: the magnetorheological fluids are premagnetized by a pulsed high magnetic field of 8 T before they are exposed to an external magnetic field for inducing the magnetorheological effect. Static and dynamic rheological measurements in the presence of a magnetic field were carried out to investigate the effect of premagnetization on the magnetorheological properties. Considering nonlinear mechanical behaviour such as instantaneous elasticity, creep and elastic delay, a four-element model, a series combination of a Maxwell viscoelastic unit and a Voigt viscoelastic unit, agrees well with the experimental data. The results evidence that the storage modulus is significantly enhanced by premagnetization.
Keywords: bidisperse magnetorheological fluids, magnetic fluids, magnetization, magnetorheological fluids, magnetorheological effect, rheological property