Magnetorheological electrorheological

Magnetorheological materials (fluids) are the magnetic equivalent of electrorheological fluids. In this case, the particles are either ferromagnetic or ferrimagnetic sohds that are either dispersed or suspended within a Hquid and the apphed field is magnetic (14). 

University of Alberta. Educational Software for Micromachines and Related Technologies. Available online. URL http //www. cs.ualberta.ca/ database/MEMS/sma mems/index2.html. Accessed May 28,2009. Research groups at the University of Alberta in Canada constructed this Web resource, which discusses a variety of smart materials, including shape-memory alloys, piezoelectric materials, and electrorheological and magnetorheological fluids. 

National Aeronautics and Space Administration—Ames Education Division Smart Materials. Available online. URL http //virtualskies.arc. nasa.gov/research/youDecide/smartMaterials.html. Accessed May 28, 2009. As part of an educational activity in which students plan an aviation research project, this Web site provides links to pages discussing piezoelectric materials, electrorheological and magnetorheological fluids, shape-memory alloys, and magnetostrictive materials. 

Scientists now understand the basic principles that determine the behavior of electrorheological and magnetorheological fluids. They believe that the imposition of an external electrical or magnetic held polarizes the particles suspended in the fluid. In the case of an... 

So far, applications for electrorheological and magnetorheological liquids are rather limited in number, but researchers predict that they will eventually find a number of applications in industry, aerospace, the military, and other fields. As with other fields of materials science, much more basic research is needed to understand the behavior of electrorheological and magnetorheological liquids before everyday applications can be developed. 

There are also complex fluids that change from solid-like to liquid-like, or vice versa, when subjected to a modest deformation. Complex fluids of this type include particulate and polymeric gels. Some fluids change to solids when an electric or magnetic field is applied these are electrorheological and magnetorheological suspensions. A classical liquid or solid, on the other hand, does not change character in response to a weak field unless it is extremely close to a phase transition temperature. 

Rheological fluids are generally a dispersion composed of a base fluid (usually a type of oil) and particles. These particles can be either polymer in electrorheological fluids (ERF) or iron based in magnetorheological fluids (MRF). If a field is applied, the so-called particle chains are built and the fluid changes its viscosity to the point of becoming a viscoelastic solid (see Fig. 11). 

A. Kawai, K. Uchida, F. Ikazaki, Effects of shape and size of dispersoid on electrorheology. In Proceedings of 8th International Conference, Electrorheological Fluids and Magnetorheological Suspensions. Edited by G. Bossis Singapore, World Scientific 2002, 626-632. 

Materials that allow an intelligent or smart structure to adapt to its environment are known as actuators. These materials have the ability to change the shape, stiffness, position, natural frequency, damping, friction, fluid flow rate, and other mechanical characteristics of adaptronic structures in response to changes in temperature, electric field, or magnetic field. The most common actuator materials are shape memory alloys, piezoelectric materials, mag-netostrictive materials, electrorheological fluids, and magnetorheological fluids [2]. Actuators with these materials will be described in detail in Sects. 6.2 to 6.6 therefore you will find only a brief overview below. 

Solid-state actuators and actuators with controllable fluids show certain similarities piezo actuators and electrorheological fluids are driven with electrical fields whereas magnetostrictive actuators and magnetorheological fluids draw their actuation energy from a magnetic field. We will therefore consider the power electronics of these two superordinate groups, but still we will mention the differences between the two different actuator types of each group. 

The electromagnetorheological effect (EMR effect) is the combination of the electrorheological(ER) effect and magnetorheological(MR) effect. Before proceeding to the EMR effect, one may need to take a brief look at the MR effect... 

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