D. Lacey et al., INVESTIGATION INTO THE USE OF LIQUID-CRYSTALLINE MATERIALS IN ELECTRORHEOLOGICAL FLUIDS, Journal of intelligent material systems and structures, 7(5), 1996, pp. 526-529
The ER activity of a number of ER fluids incorporating liquid crystall
ine (LC) and non-LC materials have been measured using a laminar-flow
shear cell. The results from this static study are presented and clear
ly show that the unique self-organising and anisotropic physical prope
rties of the LC materials contribute greatly to the ER activity of LC
based ER fluids. A more in-depth evaluation was then carried out on a
LC based ER fluid which involved measurements of the steady state beha
viour, under various operational conditions, and the results compared
with those from two conventional silicone based fluids. From this dyna
mic study it was found that within the shear rates tested, for an elec
tric field strength above 1 kV mm(-1) there existed a linear relations
hip. culminating in a shear stress of 12 kPa at an electric field stre
ngth of 4 kV mm(-1). The unique property of the shear stress increasin
g with increase in the shear rate makes LC based ER fluids an exciting
area for further research and this could be of considerable importanc
e in their use in a variety of control systems.