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Caractérisation et modélisation causale d'un frein à liquide magnétorhéologique en vue de sa commande

Abstract : Magnetorheological fluids are suspensions of micrometric magnetic particles in nonmagnetic fluids. When such a fluid is exposed to a magnetic field, the particles agregate into "chains" which increase the flow resistance highly. In this dissertation, we present the design of a discoid magnetorheological fluid brake and its characterization in two operating cases. In the first one, the brake axis rotates under constant input current, its speed being slowly and repeatedly varied following a triangle shape. The input current is changed during the rest intervals between two triangles. We could observe that the torque must typically increase until a threshold to allow the axis rotation to initiate, then it "falls" and increases again when speed increases. We also noticed that the torque thresholds measured in the first triangles of speed after changing the current differ from the thresholds measured in the following triangles, which repeat. A modelling of the brake, only valid for the maximum permissible current of the brake and in the case that at least one triangle of speed has been performed, was presented. This modelling, which was built up using the Causal Ordering Graph (C.O.G.) formalism, could match the evolution of torque when the rotation of the axis initiates in the first triangle of speed, but not in the following triangles. In the second operating case, the brake axis rotates at constant speed under slowly varying input current. Different plots of the hysteresis of torque versus current were obtained. These plots could be modelled precisely using a 2D Finite-Elements analysis of the brake and a hysteretic behaviour law for steel.
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Contributor : Ecole Arts Et Métiers Paristech <>
Submitted on : Friday, November 27, 2009 - 8:00:00 AM
Last modification on : Friday, July 17, 2020 - 2:53:31 PM
Long-term archiving on: : Thursday, September 30, 2010 - 9:17:01 PM


  • HAL Id : pastel-00005484, version 1


Richard Demersseman. Caractérisation et modélisation causale d'un frein à liquide magnétorhéologique en vue de sa commande. Sciences de l'ingénieur [physics]. Arts et Métiers ParisTech, 2009. Français. ⟨NNT : 2009ENAM0021⟩. ⟨pastel-00005484⟩



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