2008 Volume 36 Issue 1 Pages 59-64
Experimental studies were performed on the response under step changes in magnetic flux density of a magneto-rheological suspension consisting of carbonyl iron particles dispersed in silicone oil. The samples were subjected to a constant shear stress. It was found that the 30 % volume fraction suspension showed the expected changes in shear rate when the magnetic flux density was increased for a short period then reduced to the original value. The 24 % volume fraction suspension did not show this behavior, tending to maintain a lower value of the shear rate even after the flux density had been re-set to the original lower value, suggesting that this suspension may be more susceptible to some form of remnant aggregation of the particles.