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Active And Intelligent Materials: Theory Meets Application

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2009 Annual Conference & Exposition


Austin, Texas

Publication Date

June 14, 2009

Start Date

June 14, 2009

End Date

June 17, 2009



Conference Session

Advanced Materials Education

Tagged Division


Page Count


Page Numbers

14.156.1 - 14.156.10



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Paper Authors


John Marshall University of Southern Maine

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John Marshall received his Ph.D. from Texas A&M University and is the Internship Coordinator for the Department of Technology at the University of Southern Maine. His areas of specialization include Power and Energy Processing, Applied Process Control Engineering, Automation, Fluid Power, and Facility Planning.

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

In applied process control engineering curriculums, such as programmable logic controllers, MR fluids are easily activated and deactivated by controllers to maintain process set points. Using these fluids in conjunction with proportional–integral– derivative programming accurately removes hysteresis effects on the process being controlled. In statics and dynamics curriculums, sheering force calculations during fluid transitions provides remarkable insight into the clutching and dampening capabilities of the fluid.


Magneto-rheological (MR) fluids are a form of “intelligent” material that change their flow characteristics when subjected to a magnetic field. Response, which takes only milliseconds, is in the form of a progressive gelling that is proportional to field strength. MR fluids can be produced that are capable of giving high shear stresses at low applied magnetic fields. The unique nature of this class of magnetic fluids allows dramatic changes in rheology to occur within the bulk of the fluid on application of a relatively modest magnetic field. The material can change from being fluid to solid almost instantaneously, the rheology of the material reverting to its original state upon removal of the field.

“Response, which takes only milliseconds, is in the form of a progressive gelling that is proportional to field strength. With no field present, the fluid flows as freely as hydraulic oil”.1 As a result, MR technology provides fast and infinitely variable control of energy dissipation of industrial and automotive devices.2 This change of state has the potential to revolutionize the control aspects of vibration and the responsiveness of hydraulic power transmission systems. “The application of magneto-rheological fluids for damping is a unique and novel approach to an age-old problem”. 3

MR fluids have existed for over fifty years. However, it is only now that fluids are available that are stable and give shear stresses that are adequate in demanding applications such as automotive damping. In fact, one automotive manufacturer is equipping several of its new (2007) vehicles with a “MagneRide Suspension” that utilizes MR fluid technology. The manufacturer claims that the MagneRide suspension provides continuous variable real-time suspension damping based on road and driving conditions. 2

Marshall, J. (2009, June), Active And Intelligent Materials: Theory Meets Application Paper presented at 2009 Annual Conference & Exposition, Austin, Texas. 10.18260/1-2--4688

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