The Model and Simulation of Magnetorheological Grease Characteristics

Abstract

Magneto-rheological grease attracts the attention as a new kind of intelligent material. Under the external magnetic force, it is difficult to use traditional mathematics model to solve and analysis internal structure because of its complexity and polytropy. The modeling and simulation for complex system using computer becomes a good way to investigate complex system. Based on the electromagnetic theory and computer simulation, this paper constructed the model of shear stress to describe the characteristic of magneto-rheological grease that is to use body centered cubic pillars model to analysis the mechanism and characteristics of magneto-rheological grease. Using matlab simulink toolkit to compose the simulation program, simulate and analysis using theoretic model, and plot the shear stress curve of magneto-rheological grease with magnetic strength and particle size, and the shearing force under zero field. The simulation and experimental results indicate that the simulated shear stress curve is coincidence with experimental curve when the density of ferromagnetic particle is low, and it is lower than experimental curve when the density is high (the variation tendency is close), which verified the accuracy of theoretical model. It needs to improve the model by considering the still friction between ferromagnetic particles.

Thermorheological properties of magnetorheological grease and its thermomagnetic coupling mechanism

“…Hu et al (2015a) found that the Herschel-Bulkley (H-B) model can describe the MRG rheological behavior effectively. He et al (2011) and Song et al (2013) established a shear stress description model of MRG and discussed the contribution of carrier and magnetic particles to shear stress of the entire system. However, in contrast to other carrier types, the soap fiber of grease will change with the change of temperature, which will eventually affect the rheological properties of MRG.…”

Research on chain-model transition identification of magnetic dipole theory for magneto-rheological fluid

“…In order to apply equation (2) to different MRFs, Song et al 23 and Tian et al 24 added shear stress t 00 produced by carrier medium when calculating MRFs' total shear stress t, that is…”

“…where m is the mean and s is the standard deviation which depict the general inclination and distribution of inclined angles of all chains, respectively, and P accounts for the number of chains in per unit area with P = 3u(2R + d)=(4pR 3 ), and D(u) = 1=( ffiffiffiffiffiffi 2p p s)e À(uÀm) 2 =2s 2 . In order to apply equation (2) to different MRFs, Song et al 23 and Tian et al 24 added shear stress t 00 produced by carrier medium when calculating MRFs' total shear stress t, that is t = t 0 + t 00 ð3Þ…”