Mechanical and Electrical Properties of an Electrorheological Fluid

Abstract

Adaptive structures contain parts whose properties may be tuned so as to suit some purpose. Certain fluids change viscosity when subjected to an electrical field. This paper concerns the behaviour of such an electrorheological fluid, ERF, which may be characterized as visco-plastic with some elasticity present. The stress response to a prescribed strain is studied in tests. Various models for describing the observed behaviour are analyzed. Results show that modelling the ERF as a Bingham fluid gives a rather close fit for low field strength. A solid mechanics model which displays yielding with kinematic strain hardening is preferred for high field strength as it then describes the observed amplitude and frequency dependence quite well. Relevant constants for investigated models are listed as functions of the field strength. The electrical behaviour is essential in designing parts for on-line response of structures, in order to control vibrations. Results show that a damper containing ERF responds to applied voltage as a capacitor whose leak resistance depends on voltage whereas its capacity does not. AC as well as DC fields are treated. When subjected to harmonic displacement the force response of the damper contains superharmonics owing to the non-linearity of the ERF. In AC powered dampers, intermodulation frequencies between field and displacement are identified.

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References

1. Lieh, J. , 1997, “Optimal Design of Active Suspensions Using Damping Control,” Journal of Vibration and Acoustics, vol. 119, pp. 609-611.

2. Janocha, H. , Reck, B. and Bölter, R. , 1996, “Practice-Relevant Aspects of Constructing ER Fluid Actuators,” International Journal of Modern Physics B, vol. 10 (23 and 24), pp. 3243-3255.

3. Mahjoob, M. J. , Martin, H. R. and Ismail, F. , 1995, “Identification of Damping and Stiffness of Smart Structures Incorporating ER Fluids,” Applied Acoustics, vol. 45, pp. 211-226.

4. Shiang, A. H. and Coulter, J. P. , 1996, “A Comparative Study of AC and DC Electrorheological Material Based Adaptive Structures in Small Amplitude Vibration,” Journal of Intelligent Material Systems and Structures, vol. 7, pp. 455-469.

5. Kamath, G. M. and Wereley, N. M. , 1997, “A Nonlinear Viscoelastic-Plastic Model for Electrorheological Fluids,” Smart Materials and Structures, vol. 6 (3), pp. 351-359.

6. Yalcintas, M. and Coulter, J. P. , 1995, “Electrorheological Material Based Adaptive Beams Subjected to Various Boundary Conditions,” Journal of Intelligent Material Systems and Structures, vol. 6, pp. 700-717.

7. Eriksson, P. E. , 1991, “Shear Properties of Two Viscoelastic Damping Materials—Low Frequency Vibration and Creep,” Proc. of the 4th International Conference on Recent Advances in Structural Dynamics, pp. 551-560.

8. Gavin, H. P. , Hanson, R. D. and Filisko, F. E. , 1996, “Electrorheological Dampers, Part I: Analysis and Design,” Journal of Applied Mechanics, vol. 63, pp. 669-675.

9. Ginder, J. M. and Ceccio, S. L. , 1995, “The Effect of Electrical Transients on the Shear Stresses in Electrorheological Fluids,” Journal of Rheology, vol. 39 (1), pp. 211-234.

10.

10. Yatsuzuka, K. , Miura, K. , Kuramoto, N. and Kazutoshi, A. , 1995, “Observation of the Electrorheological Effect of Silicone Oil/Polymer Particles Suspension,” IEEE Transactions on Industry Applications, vol. 31 (3), pp. 457-463.

11.

11. Lou, Z. , Ervin, R. D. and Filisko, F. E. , 1993, “The Influence of Viscometer Dynamics on the Characterization of an Electrorheological Fluid under Sinusoidal Electric Excitation,” Journal of Rheology, vol. 37 (1), pp. 55-70.

12.

12. Prager, W. , 1948, “The Stress-Strain Laws of the Mathematical Theory of Plasticity,” Journal of Applied Mechanics, (15), pp. 226-233.

13.

13. Vesterberg, O. , 1989, “History of electrophoretic methods,” Journal of Chromatography, (480), pp. 3-19.

14.

14. Fujita, T. , Wada, Y. , Obinata, G. , Akagami, Y. , Nishimura, S. and Ogasawara, Y. , 1996, “Comparison of Frequency Characteristics in a Damper Using Magnetic Fluid, ER Fluid Dispersing Smectite, and Mixed ER Magnetic Fluid,” International Journal of Modern Physics B, Vol. 10 (23 and 24), pp. 3001-3010.

15.

15. Firoozian, R. , 1996, “A Non-Linear Model for Dynamic Response of Electro-Rheological Fluid in Flow Mode,” Journal of Intelligent Material Systems and Structures, vol. 7, pp. 489-493.

16.

16. McLeish, T. C. B. , Jordan, T. and Shaw, M. T. , 1991, “Viscoelastic Response of Electrorheological Fluids. I. Frequency Dependence,” Journal of Rheology, vol. 35 (3), pp. 427-448.