Dynamic Viscoelasticity and Its Mechanical Model of an MR Suspension in Oscillatory Slit Flow Mode

Abstract

The dynamic nonlinear viscoelasticity of an MR fluid in oscillatory slit flow under magnetic flux normal to the flow has been investigated by using a newly developed oscillatory pressure flow type rheometer. The MR fluid consisting of micron-sized magnetically polarizable particles (carbonyl iron) dispersed into a carrier medium (hydrocarbon oil) was evaluated. The dependence of viscoelasticity of the MR fluid on magnetic field strengths, fluid strain amplitudes and fluid oscillation frequencies have been already investigated. Generalized viscoelastic mechanical models of the MR fluid in oscillatory slit flow are very important for analyzing various MR dampers using MR valves. In this work, a nonlinear dynamic viscoelastic mechanical model of the MR fluid in oscillatory slit flow is proposed, based on the data which have been already measured. The proposed viscoelastic mechanical model of an MR fluid is discussed and compared with the experimental results.

References

Carlson, J. D. 1994. "The promise of controllable fluids," Proc. ofActuator 94, 266-270.

Gamota, D. R. and F. E. Filisko . 1991. "Dynamic mechanical studies of electrorheological materials: Moderate frequencies," J. of Rheology, 35(3):399-425.

Jolly, M. R. and M. Nakano . 1998. "Properties and applications of commercial controllable fluids," Proc. of Actuator 98, 411-416.

Nakano, M. , H. Yamamoto and M. R. Jolly . 1998. "Dynamic Viscoelasticity of Magnetorheological Fluid in Oscillatory Slit Flow," Proceedings of the 6th International Conference on Electro-Rheological Fluids, Magneto-Rheological Suspensions and their Applications, editors M. Nakano and K. Koyama , World Scientific, 551-559, and 1999. Int. J. of Mod. Physics B, 13(14 & 15):2068-2076.

Powell, J. A. 1995. "Application of a nonlinear phenomenological model to the oscillatory behavior of ER materials," J. of Rheology, 39(5): 1075-1094.

Weiss, K. D. , J. D. Carlson and D. A. Nixon . 1994. "Viscoelastic Properties of Magnetoand Electro-Rheological Fluids," J. of Intel. Mat. Syst. and Structures, 5(1 1):772-775.

Yamamoto, H. and M. Nakano . 1998. "Dynamic Viscoelasticity and Viscoelastic Model of an MR Fluid in Oscillatory Slit Flow," Proceedings of the 4th International Conference on Intelligent Materials, 132-133.