Preparation and rheological properties research for silica based magneto-rheological viscoelastic fluid (MRVF)

In order to overcome the particle sedimentation issue of MRF,along with the small control range trouble of MRE,a new MR material,named as magneto-rheological viscoelastic fluid(MRVF),was put forward.The carrier of MRVF was based on the chemical products of hexamethyldisiloxane and polyborodiphenylsiloxane.By means of ball milling method and special additives,four samples are developed.The rotary rheometer,Austrian Anton Par MCR-301,was used to test the rheological properties of the samples.The experimental results show that the shear stress varies from 5 to 120kPa with the shear rate of 200s-1 and magnetic induction intensity of 0-0.9T.According to the curves of shear stress versus shear rate,Gaussian Function was adopted to describe the constitutive model,and the least square method was applied to identify the parameters of the model.The shear stress decreases less than 10% with temperature increasing from 25 to 80℃.After standing for three months,the sedimentation rate of the samples was less than 4%.