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An electro-rheological model based in Voigt units which takes into consideration the variation in volume promoted by electrostriction is developed. The model was based on a mean field approximation as an averaging of the mechanical and electrical properties. The electro-rheological coupling which describes the effects of the electrical excitation on the mechanical response and the effects of the mechanical excitation on the electrical response of the dielectric is studied. In the case of an alternating electrical excitation the model reveals the appearance of harmonics in the current through the dielectric promoted by the electrostriction phenomenon. In contrast, for the case of an oscillating mechanical excitation, a current which overtakes the driving mechanical oscillation was resolved to appear. The correlation of the new model with experimental results, obtained from dynamic mechanical analysis tests conducted under high electric field, in polyamide, was found out. [ABSTRACT FROM PUBLISHER]

A novel electro-rheological model for liquid and solid dielectrics is presented, which is well adapted to the purposes of engineering calculations. The study is focused in the frequency range of relaxation processes, well below the optical range. In addition, the dielectric material is considered to have only polarization charges, i. e. conduction charges are absent. The description for the energy transfer processes in dielectric materials is based on one-dimensional approximation using a rheological model with two- and three- parameter Voigt elements. The mean field approximation is adopted, considered as an averaging of the mechanical and electrical properties for the dipole and inter-dipole spaces. The continuity condition for mechanical and electrical forces is also taken into account. The model was applied to the study of ethylene-propylene- dyene monomer (EPDM) commercial rubber having two phases, amorphous and semi- crystalline. A good agreement was found with the experimental results from dielectric relaxation and dynamical mechanical measurements. [ABSTRACT FROM AUTHOR]