The Study of Magnetorheological and Electrorheological of Magnetite Suspension

• Main Authors: S.T You, 游士德
• Other Authors: Syang-Peng Rwei
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/10556889919405457525

碩士 === 國立臺北科技大學 === 有機高分子研究所 === 92 === This thesis is composed of two parts. The first part is focused on the investigation of magnetorheological (MR) fluid. The magnetite particles (Fe3O4) were synthesized by colloidal reaction method and characterized as a normal size distribution with 10 nm in average by XRD and TEM. Experimental results reveal that the MR effect increases with the magnetic field and suspension concentration. It was found that the addition of less than 1 % by weight of Fe3O4 particle can significantly raise the viscosity of suspension up to 2 orders of magnitude as the sample subjecting to a magnetic field of 146 Oe. The yield stress of MR fluid increases proportionally to the magnetic field strength. Moreover, the MR effect caused by DC was found to outperform that done by AC within the same current. The second part deals with the ER effect with the Fe3O4 particles dispersed in a PDMS (polydimethylsiloxane) bath. The results show that the Maxwell-Wiechert Model with two units, one represents the viscoelasticitic behavior of PDMS and the other illustrates that of ER particles, can perfectly depict the ER behavior as we observed. The relaxation time τ2 for the ER particle was found to increase with the electric field and the suspension concentration.