Resistance of a Commercial Magnetorheological Fluid to Penetration.

摘要

The stress required to penetrate a commercial magnetorheological (MR) fluid exposed to an applied magnetic field, B, in the range of 0 - 0.25 Tesla was determined for: (a) a constant, continuous field and (b) on-off field. With constant field application, it was found that vs. the penetration depth, x, of the cylindrical indenter into the MR fluid at a constant rate of 0.12- 0.18 mm/s was parabolic in form, namely = (sub o)x(expn n) where (sub 0) = AH, A = 1.7 kPa/(kA/m) and n = 0.3-0.5. The magnitude of o is approximately six times that of the shear yield stress, (sub y), of the MR fluid. A model is proposed to explain the resistance to penetration into the MR fluid with the constant field. The results obtained in the on-off field tests and the in-out tests are in keeping with the model.