MATHEMATICAL-MODELING OF THE DYNAMIC-RESPONSE OF ELECTRORHEOLOGICAL FLUID

The dynamic response of electro-rheological (ER) fluid is studied and it is shown that the current response to a change in the applied volta ge can be modelled accurately by a simple nonlinear RC network. Variou s models proposed in the literature are studied and are compared with the simple model. When the voltage is applied across the electrode of an ER device the yield stress changes from a zero to a finite value. I t is concluded that the dynamic response of the yield stress cannot be measured from test in flow mode. However, by employing a simple signa l processing technique the dynamic response can be estimated in shear mode. The dynamic response of the yield stress is modelled by a second order transfer function characterized by a natural frequency and a da mping ratio.