A large scale test of a conduction model of the electrorheological effect

A conduction model is proposed to explain the electrorheological effect under DC or low-frequency AC fields. An approximate analysis taking into account the bulk conduction of the solid and the nonlinear conduction properties of the liquid is confirmed by experiments on large-scale spheres. Measurements of the attraction force between two weakly conducting spheres performed on the large-scale model confirm the analysis based on the picture of electric field and interfacial charge distributions being controlled by the conduction properties of both media and not by their permittivities. Under DC (and low-frequency AC) fields this has been clearly shown for air as well as for nonpolar dielectric liquids. The predictions are extended to the case of surface conduction of the solid spheres