The Segregation Problem of Magnetorheological Fluids in Squeeze Mode - An Experimental Investigation

In this paper the squeeze mode behaviour of a certain magneto-rheological fluid (MRF) is investigated. Special attention is paid to the analysis of the achievable squeeze forces for very thin and slender squeeze gap geometries. In case of repeated squeezing the problem of segregation is faced usually. The avoidance of this phenomenon (which is also sometimes called clumping effect) is one of the major problems of such high force density MRF squeeze mode applications. Therefore, a new anti-segregation approach, namely an elastic MRF reservoir of minimum volume that absorbs the MRF in compression phase and pushes it back into the gap in expansion phase, is experimentally analysed in more detail. A cogent explanation of the segregation mechanism, in particular of its evolution during compression and expansion phases, is given based on the experimental set-up and special experimental procedures.