Resonance response of electrorheological fluids in vertical oscillation squeeze flow

The resonance effect of microcrystalline cellulose/castor oil electrorheolo gical (ER) suspensions was studied in a compressed oscillatory squeeze flow under external electric fields. The resonance frequency first increases li nearly with increasing external held, and then shift to high-field plateau. The amplitudes of resonance peak increase sharply with the applied fields in the range of 0.17-1.67kV/mm. The phase difference of the reduced displac ement relative to the excitation force inverses in the case of resonance. A viscoelasticity model of the ER suspensions, which offers both the equival ent stiffness and the viscous damping, should be responsible for the appear ance of resonance. The influence of the electric field on the resonance fre quency and the resonance hump is consistent qualitatively with the interpre tation of our proposed model. Storage modulus G' was presented for the purp ose of investigating this influence.