Extensive computer simulations were carried out to examine the structures of electrorheological (ER) fluids. In a weak electric field, ER fluids move from a liquid state to a nematic-liquid-crystal state that has ordering only in the field direction. If the electric field is strong and thermal fluctuations are weak or moderate, ER fluids develop into a body-centered-tetragonal lattice. A very strong electric field with very weak or no thermal fluctuations may force ER fluids into a polycrystalline structure. When both the electric field and thermal fluctuation are strong, ER fluids develop into a glasslike state, in which the particles aggregate together to form thick columns, but the structure has no appreciable ordering. The simulation has also shown that the solidification time and chain formation time in ER fluid systems depend mainly on the ratio of the viscous force to the dipolar force.

• Received 11 October 1996

DOI:https://doi.org/10.1103/PhysRevE.56.4328