Polyaniline coated ZnFe2O4 microsphere and its electrorheological and magnetorheological response

Magnetic/conducting polymeric hybrid core-shell typed zinc ferrite (ZnFe2O4)/poly(N-methyl aniline) (PMA) particles were fabricated and adopted as electrorheological (ER) and magnetorheological (MR) fluids, and their rheological properties were examined. Solvo-thermally synthesized ZnFe2O4 was coated with a conducting PMA through chemical oxidation polymerization. The size, shape, and chemical composition of the final core-shell shaped particles were scrutinized by scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy. The crystal faces of the particles before and after coating with PMA were analyzed by X-ray diffraction. The ZnFe2O4/PMA products were suspended in silicone oil to investigate the rheological response to electro- or magnetic stimuli using a rotating rheometer. The shear stresses were analyzed using the CCJ equation. The dynamic yield stress curve was suitable for the conductivity mechanism with a slope of 1.5. When magnetic fields of various intensities were applied, the flow curve was analyzed using the Hershel–Bulkley equation, and the yield stresses had a slope of 1.5. Optical microscopy further showed that the particles dispersed in insulating medium form chain structures under electric and magnetic fields. Via this core-shell fabrication process, not only spherical conducting particles were obtained but also their dual ER and MR responses were demonstrated for their wide potential applications.

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Dual Electrorheological and Magnetorheological Behaviors of Poly(N-methyl aniline) Coated ZnFe2O4 Composite Particles

This paper presents the effect of a magnetorheological (MR) damper in the aircraft seat system on the body's biodynamic response for different flight maneuvers. For this purpose, discrete models 4 and 7 degrees of freedom for human modeling and the Bouc-Wen model are used to model MR damper. In various flight maneuvers, the changes in acceleration g are recorded and applied to the desired models after processing. Models used for the human body and the MR damper are compared for validation with previously published researches. The dynamic responses of the human body to these inputs without MR dampers and with an MR damper are investigated. The transmissibility[1] of the seat to the human body is used as a parameter that is common in these types of analyses. The results show that the use of MR dampers has a significant effect on reducing the transmissibility in maneuvers with a sudden increase in acceleration and also significant changes in the frequency at which maximum transmissibility is achieved.

The influence of magnetorheological dampers on the biodynamic response of the human (pilot) body in various flight maneuvers

In last two decades research on the topic of synthesis, characterization and analysis of smart fluids like Magneto rheological (MR) and Electro rheological (ER) fluids is taking place. In this paper researchers working in experimentation, development of mathematical model by Bingham plastic model and Herschel-Bulkley method have been studied. MR/ER fluid have main advantage, that is its unique property, means Bingham plastic properties. The verification and validation of result of damping force and damping displacement depends on the application of an external magnetic field or no field. Developing the theoretical model of fluid flow for annular duct of two parallel plates or circular duct is done. And study of Newtonian and non Newtonian fluid flow by computational and numerical method.

Abhijeet N. Kulkarni

Papers

Magneto-Rheological (MR) and Electro-Rheological (ER) Fluid Damper: A Review Parametric Study of Fluid Behavior