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Spectral analysis for response of the dynamic damping force and phenomenological modeling of electro-rheological fluid

The dynamic mechanical properties of an electro-rheological (ER) fluid composed of polyaniline particles in silicon oil is studied under the shearing state. By applying sinusoidal signal with different frequencies and different shear strain amplitudes, the response of ER fluid damping force has been measured and analyzed. The result shows that the damping force of ER fluid is linear without electric field, and is nonlinear when an electric field is applied. By using the frequency spectrum analysis of the response, we found that the harmonics frequencies of the damping force are odd multiples of the fundamental frequency, and the damping force has bilinear hysteresis property. A simple damping model of ER fluid is given in this paper. The comparisons of the experimental results with those of the numerical simulation show that the model of ER fluid setting up in this paper is reasonable.